yard. >> we know the queen is safe in buckingham palace, we know the prime minister theresa may is safe, they won't tell us where she is. we'll continue our coverage. thank you for watching this hour of "msnbc live." our coverage continues with "andrea mitchell reports." >> and good day, i'm andrea mitchell in washington. where we are of course following breaking news out of london, reports of two violent incidents outside parliament. first on the westminster bridge, reports of a vehicle hitting and injuring several people, then eyewitnesses say a man with a knife charging through the gates outside of parliament, a police officer was stabbed and then the assailant was shot by police. scotland yard is treating this as a terrorist incident. parliament is on lockdown. this was the moment in the house of commons. >> order. i am now going to suspend the sitting of the house. this house is now suspended but please, wait here. >> president trump has been briefed about the incident at

the white house. we have full team coverage starting with nbc's matt bradley, who was near number ten downing street. matt? >> reporter: hi. andrea, it's matt. we're here at white hall street right down the street from ten downing street, the official residence of prime minister theresa may. we can't see the action directly in the house of parliament but we can see flashing lights and ambulances, police cars, other emergency vehicles darting back and forth attending to the situation. as you mentionmentioned, scotla and the metropolitan police say they'll treat this as a terrorist incident until they know more. associated press was quoting mi5 the domestic intelligence agency for the uk said they weren't going to be treating it as a terrorist incident until they know more. this is two separate law enforcement agencies in britain kind of treating this differently, but the fact

remains is that this is still a very volatile situation, quite a lot of people who cverged on this. do you remember last year the british police announced in response to terrorist attacks throughout europe that they're going to be deploying some 600 additional police officers to central london, who would be armed, some of them with long weapons, and that's new, of course, and britain, police don't typically carry live ammunition with firearms. they'd sometimes carry stun guns or just carry batones or nothing at all. that shows it's another indicator of the city on tenterhooks waiting for the other foot to drop when it comes to terror like we've seen throughout the rest of europe. right now we're waiting for more information and just waiting to see emergency vehicles kind go of back and forth and try to treat this situation. andrea? >> matt, kelly cobiella is in our london newsroom. we're looking at big ben and the

houses of parliament, what do we know about how many people may have been injured in the incident or series of incidents? >> it's not clear, andrea, how many people were injured at this point. there are initial reports were based on an eyewitness report at the scene. reuters photographer, in fact, who said he saw at least six people injured on westminster bridge. that would have been a very busy bridge at that time of day, foot traffic on both sides of the street, bicycles, people going in between jobs to meetings, lots of tourists in that area, as you know. so it would have been crowded. how many people were actually struck by that car, which has been described as a 4x4 which we believe sort of a smaller sized 4x4 like a small suv, we simply don't know. it wouldn't have been particularly high speed. it would have been very congested traffic. however, either it doesn't take much and we have seen some fairly severe injuries just

based on photographs. we haven't had any confirmation on how serious any of the injuries are, but you can see from the pictures, andrea, as well, the response to this, several ambulances, emergency vehicles, and air ambulance flown right down onto parliament square this afternoon. so clearly a number of casualties. we're just not clear how many. we also don't know if there are any deaths at this point. we're hearing very limited information from met police. police are asking people to stay out of the area. they've closed a lot of the roads in this very central part of london. they have closed westminster tube station, which if you're familiar with london you'll know that takes you right to the corner of parliament square, where you can see big ben, the houses of parliament, and the bridge. so that has now been closed down. parliament is on lockdown. we've heard from lawmakers inside that they've been told to

stay in their offices, keep themselves barricaded inside until they get the all clear. as far as we know, that has not happened yet. there is still no all clear inside that building. and it sounds, andrea, like there were two incidents. however, we're not clear yet whether this was all perpetrated by one attacker, or more than one attacker, and that most likely is the reason that there is still a lockdown here. we understand it may have started on the bridge, that's what we're hearing from our witnesses, that they first heard something happening on a bridge, on the bridge. they thought perhaps it was a traffic accident. then they heard commotion at the gates, going into parliament, these are the gates that take cars straight in to parliament, one of our witnesses said he looked out the window, he saw what he describes as a heavyset man running through the gates toward a police officer, carrying what looked to be some sort of weapon, possibly a

knife, attacking the police officer who then fell to the ground. he managed to get away, and the attacker was shot. this is all according to our eyewitness. we also have heard from the house of commons leader that in fact an officer was stabbed, an attacker shot by police, but in terms of casualties at this point, and potential suspects, andrea, those are still question marks. >> and kelly, just to clarify, it did appear from the initial pictures, was this, did this take place while parliament was in question time, which i think beg wednesday, it would have been? were they in session? >> i would have to double check. they were absolutely in session, as you'll know, prime minister's questions happened a little bit earl whier in the day, around noontime locally. i'm not sure how long they went today, but the prime minister was in parliament earlier today, around noon, holding prime

minister's questions, talking to lawmakers about, debating the back-and-forth about the government's policies. we understand that she is, we're not sure if she was at the houses of parliament when this happened. what we're told from number ten, from her official spokespeople is that she is safe, and at work. they're not disclosing her exact location. but as you know, this would have been an extremely busy day at the houses of parliament, when you have prime minister's questions, you usually have a full house of commons. you have lots of lawmakers there, ready to take on the prime minister, parties shouting out their policies against one another, so it would have been a very, very active day there. and on top of that, you have the civil servants, you have reporters. you have lots and lots of people who have business inside this massive building known as westminster palace. >> and just to also inform our viewers, the equivalent of our secretary of state, the foreign

secretary, boris johnson, is in washington. he was seen earlier today. he is at the state department for a summit of 27 or 28 nato members, who are all participating in a summit being led by secretary tillerson on new strategy, which is actually similar to the obama strategy on how to counter isis. so british officials are here in full force in washington. they have meetings going to the u.n. tomorrow, where he's supposed to lead the u.n. general assembly, rather the security council. so there is a big contingent of british tip ldiplomats here in washington, d.c., as well. jeremy bash is an nbc news national security analyst, previously serving as the chief of staff to leon petta at the cia and the pentagon. jeremy, let's talk about how intelligence, how british security would begin to drill down on who these perpetrators could be, whether these are linked, whether there is one incident, two incidents, whether

one is a diversion. what would be going on today? >> the lead agency inside london today, andrea, will be the british secret service, mi5, their internal security service, and they will work hand in hand with new scotland yard to look at any potential evidence le linking these assailants to known terrorist associations, look at the car, make and model and take the plates and biometric information from the alleged assailant who was shot trying to get into parliament. they will look at social media and tear apart any potential online claims by any individual or organization claiming to speak in the name of isis, al qaeda, or any known terror organizations. they will take that information, compile it, and figure out number one, who these people are, number two, if they're linked to any broader network inside the uk or throughout europe, and number three, if there are any other attacks planned. it's worth noting, andrea, this comes one day after the uk joined u.s. homeland security officials in warning about

terror attacks, probably from isis, in taking electronics, large electronics on board aircraft, emanating from the middle east on certain middle eastern air carriers. the uk joined that terror warning yesterday. they modified it to some extent but they joined it and it's not clear whether or not this potential apparent terrorist attack is in any way connected to that threat stream or potentially a response to that move by british authorities. >> and jeremy, let me just also expand on that, because there is no intelligence agency closer to the u.s. intelligence agencies than the british. we know that in the last couple of days there was a disruption because of the suggestion from the white house that the british intelligence were somehow involved in the initial false claim of wiretapping against trump tower by former president obama, that was denied,

apologies were called for. i've been talking to officials to diplomatic officials and they say that they have gotten past that, so that there is a smooth coordination between u.s. intelligence and british intelligence, and certainly would be in this instance, despite the political noise, if you will, that's been surrounding it. jeremy? >> yes, these are our closest partners in the world by far, and i think they are resolutely focused on the fact that the uk has been in the bull's eye of isis' target for many, many years, as of course your viewers will recall, al qaeda targeted london multiple times, including the horrific attacks in 2005, targeting the transport systems, and more recent years, isis talked publicly about attacking british individuals, british citizens, there's been a lot of concerns about terror organizations having networks of individuals in london and traveling through the uk, so thiss defitely a focus are for u.s. and uk intelligence

officials. of course, we don't know at this hour what these individuals were motivated by, but the fact that they were simultaneous attacks, the fact that there was a car ramming episode, which seems to look like the car ramming episode that took 70 people's lives, 73 people's lives in east france last year, and a knife-wielding attack on the beating heart of the uk's democracy, the parliament there in downtown london, that causes a working hypothesis to emerge, and a working hypothesis at this hour, i believe, andrea, has to be that this is an isis-inspired attack, attack inspired by isis elements, headquartered in raqqah, in syria, and those operating in the iraq and syria area, and that this was inspired and put out either online in social media or other communications channels to attack british targets, that these individuals are part of that network.

now again, that's just a hypothesis at this hour, and intelligence officials will run that to ground every way they can. >> and let's just also put in context the fact that there is this anti-isis summit right now at the state department, that in talking to diplomatic officials, including british officials, part of the predicate is that there is a lot of activity, that they have gained ground -- excuse me -- gained ground against isis in mosul, that they are beginning to organize the attack in raqqah, that isis is losing territory, and presumably, jeremy, they would be wanting to strike out and prove that they are still viable force, as they lose territory in iraq and presumably soon in syria. i wanted to also bring in by phone "daily express" report camella trmany currently locked inside parliament. can you talk to us what is going on and what you saw at the time

and what is going on now? >> sure, andrea. it's a little bit of an update here journalist next to mes that learned there may well have been a package found in a car near the house of the parliament and that's why the lockdown has been necessitated, not only by the earlier shooting, but the notion as your previous correspondent was saying that there's a series or simultaneous number of incidents here, which actually now the last one being thwarted because the bomb squad has been involved in this operation. so earlier today at about quarter to 3:00, just after prime minister's questions, when the house was very full, because theresa may gives her weekly address to parliament, where all of the politicians and journalists and everybody who is visiting the palace have coffee was suddenly subject to some sort of incident, there was some shouting, there were people who run up from an escalator from the cloisters, which is the main outside cor dhar that links the old palace to the newer part that i was in.

gunshots were heard and police were suddenly flooded the area, told everyone to run, run, run. we were pushed to the back of the building. now i'm in a group of people that is being pushed even further east through older buildings to get away from the main area where we believe, a, the assailants were shot, and b, there may well have been a suspicious package in a nearby car. >> and camilla, since 2005 security has been increased in the states since 2001 our own building, our own congress which used to be completely accessible has been barricaded and shut off and certainly we've seen the incidents around the white house which have changed the existence here in washington. how has it changed since 2005, and since all of these other incidents by isis elsewhere in europe as far as security, and access to the buildings in westminster? >> well, essentially anybody that comes into the palace of westminster has to have a part, and they get assigned a pass

after jumping through various complicated security hoops involving where they've been born, where they live, what their parents did and all the rest of that. you have to be vetted to have a pass. now i have a journalist pass, many have mps, many staff passes. once you have a pass you are able to get visitors in but they have to go through quite rigorous x-ray and bag check system that involves the conveyor baggage checkers you find at the airport. obviously your viewers would have heard there's an attempt to breach one of the security gates at old palace yard. that is the yard where cars come in and out, even the prime minister's car might come from downing street for instance so basically the penetration has happened at the heart of this main precinct, close to the area where you see people walking from one part of the chamber, where they might hold their debates to where the coffee houses and restaurants are located. it's the central hub

essentially. so yes, security's been tightened, as you would imagine, and there is a rigorous screening for people to have passes to exit and enter the building and indeed visitors are screened on entry. nobody can just walk in here. there is a very secure screening process. >> boris johnson is here in washington at a summit that's been convened by the secretary of state here against isis, and on how europe, how nato members can jointly combat isis. they say they are winning, that isis is retreating, and as we see live pictures now of this summit from our state department -- >> sure. -- >> johnson and others here have been saying they are making progress with the, beginning to retake mosul, with i is going to be a long time-consuming military operation, and then move on to raqqah in syria. but how stiff is the will of the british people? are they committed to this, and

will these incidents create political problems for the alliance? >> well, i think really the british stiff upper lip is always in evidence and when things like this happen, we keep calm and we carry on, that's our mentality and that happened with 7/7 and subsequently. the general air in like it was in paris, covering the duke and duchess was affected by a terrorist related incidt and a man trying to shoot at police officers and then being shot dead in orly airport. often there is a case of when, not if, terrorist attacks will happen on these soil and anyone in the western world who has got an aggressive and outspoken approach of it people like islamic state daesh, let's face it, boris johnson hasn't been shy in coming forward in his utter condemnation of terrorists and that should be the case but of course we're targets here. it's also a very politically delicate time. we've got theresa may triggering

article 15 next week and it's a very, very busy time westminster particularly on a wednesday, that's when she does her weekly questions in parliament, so parliament is always very full. generally two weeks away from recess, when parliament breaks up so to speak for the easter vacation. there's a lot of activity going on to finish things off before the easter break, and a sense that the time of this does coincide with one of the busiest times here when parliament is most likely to be chock full. >> and of course, when you spoke of article 15 you're talking about the beginning of the divorce with the european union from brexit that has to be initiated as well. thank you so much, and i know you're going to be, you are staying on lockdown there. i wanted to just bring in for a moment congressman adam schiff, who is the top democrat on the house intelligence committee. congressman schiff, we've been talking to jeremy bash about what would be going on with security in london, the fact

that this may be simultaneous attacks, that it may be well coordinated, the initial suspicion would certainly be toward isis especially after the intelligence that led to the banning of laptops between the brits and the u.s. on flights coming in from certain countries. would that be a safe assumption? >> well you know, i think certainly the operating assumption would be either isis or al qaeda. i think it's very early to tell and probably the paramount priority now for the british is to figure out are there other people involved? is there still an ongoing threat? are there other targets that have not yet unfolded in terms of the attack, that's got to be the most immediate priority. obviously we're reaching out to the british to help in any way to chase down any leads that we can to run any names that they may have through our databases to be of whatever assistance we can. this looks to me an awful lot like the tact we saw in canada in and around the parliament as well, and as jeremy said, this could be a situation where

people were inspired by either al qaeda or isis, or it could be a situation where people are acting under direct command and control of a foreign terrorist organization. we don't know at this point, but again, i think probably the most immediate priority is just to figure out right now for the brit shall do they face an ongoing threat that is still unfolding. >> and in terms of the threat that the british and the u.s. acknowledged yesterday, regarding the banning of laptops prospectively from flights from certain countries, how immediate was that threat? how specific was that threat? can you talk at all about the intelligence that led to that decision, and highly unusual decision? >> i can only say we're continually briefed on aviation targets by foreign terrorist organizations. obviously they have always put a high priority on aviation, and for good reason. it can cripple an entire industry.

it certainly has the ability to terrorize people and it's very vulnerable. it's hard to protect aircraft from explosives and do so on a global basis, so we're continually getting updated briefings on how our adversaries are adapting to our security measures, and as we see them changing their tactics, as we see them improving their ability to get around our security measures, we also have to adapt, and the only thing i can say, because i can't go into specifics, is that i think the steps that we are taking, the steps that british are taking are fully necessary. i think they're proportionate to the threat. i still think frankly there is he a lot more we need to deal with the aviation threat, but i wouldn't jump to the conclusion that that issue is necessarily connected to what we're seeing in britain. these two be could two-completely separate disparate issues, and i think it's far too early to draw any connections. >> and how would you characterize for our viewers the closeness of the relationship between our intelligence

community and the brits? >> you know, completely shoulder to shoulder. these are our closest partners, and dearest friends, and most stalwart allies. we have some other great partners as well who are equally devoted, us to them and them to us. so this is a very important relationship. i think it's fair to say that, when the british are attacked, the american almaeramericans al. our hearts go out to our british friends who are enduring this now. all too familiar problem, here in the united states, and regrettably around the world. >> and ordinarily when something like this happens, at our own counterterrorism center, what they would do, to go back over the stream of all incoming communications to see if they see anything that would signal a threat against our british allies, correct? >> absolutely. the british will be doing this, our own intelligence agencies will be doing this, and the moment that the british have identified anyone will be

running them through our systems as well to figure out is there anything in our holdings that sheds light on who their associates may be or what other plots may be out there or are there digital devices that the british have obtained that will allow us to run numbers and determine whether their connections to people obviously here but in britain or anywhere else in the world. >> you do not know of any threat, any threat matrix that preceded these attacks in london today? >> well, i'm not aware of any specific and credible information that we knew that the britains may be the subject of an imminent attack. certainly if we had that kind of information we would be sharing that with the british. now that hasn't come to my knowledge. it's certainly possible that there is some information out there, but i'm not aware of that kind of specific or credible threat information. i certainly have been briefed on the aviation threat, but again, i wouldn't necessarily draw a link between the two. i think it's far too early to be

reaching that kind of a conclusion. >> congressman adam schiff from the intelligence committee, thank you so very much. >> thanks, andrea. >> number ten downing street confirms that theresa may, the prime minister, has returned to number ten. just to explain, number ten is a very small relatively small building, much smaller than the white house, connected with number 11, which is the residence and office of the chancellor of the x checker. they are set back from the street behind an iron fence, but very accessible to correspond t correspondents, to stake-out crews, much more accessible right across the way to much more visible than anything that we encounter here in the u.s., except that you would be behind the fence on the north lawn of the white house. it would be similar to that, but she is in number ten, and is monitoring the situation from there. malcolm nance has spent 30 years as a counterterrorism and intelligence officer and joins

me now. malcolm, first i wanted to play some eyewitness accounts, two women who were on the westminster bridge and saw it all go down. >> we heard what we thought was gunshots, turned around, saw a car plowed into a lady, there was bodied literally -- >> about ten bodies. >> 10 or 12 bodies. >> lying in different places along the bridge. >> it was horrendous. absolutely horrendous. >> malcolm nance, the brits, as you know, have decades of experience with counterterror operations. we have the extraordinary situation back in the '80s, where at a labor conference, the prime minister, margaret thatcher, was almost assassinated with an i.r.a. bomb so they went through years and years of dealing with this on a daily basis, and we were talking to a daily mail correspondent who is on lockdown inside and said the brits have a stiff upper lip still. this is the heart, the soul, the

pulsing beat o democracy in our closest ally. >> you're absolutely right, and england is no stranger to this, but let's take a look at this attack objectively. it appears to have been done with very simple methodologies and we're starting to assess here that the vehicle actually would have hit four or five different places along westminster bridge, where it ran over pedestrians before going up to the parliament and discharging either the driver or passenger, who came out and assaulted the police officer and then was shot. that's pretty much what we're getting right now. that explains all of the casualties on that bridge. but a very simple methodology, a combination of this, you know, vehicle as weapon system, as we've seen in israel and france, and then an armed assault with what was at hand, a machete or a knife, against an individual police officer. that is not the methods that the

irish republic army used. they blew up bombs trying to kill the prime minister, blew up bombs attacking the royal horse guard on parade, and did armed assaults. however, this method works for people who are followers of isis who are self-inspired, to go out and carry out attacks, as isis starts to collapse, and there is virtually no way to predict this type of attack. >> no way to predict, and no way to protect against? >> in this particular instance, no. the first segment of it appears it's what we call a vehicle as weapons system attack. where you take your car and you just start driving over pedestrians on a crowded bridge, may have been on a walkway coming off from westminster, and you just hit them as you see them, and then go on and conduct your assault, which is just a man with a knife or a machete. you don't know what's happening until it's actually in place.

as you see it had a lethal ending, but it's also cost other people their lives. >> and another eyewitness who talk to ou correspondents there, who was on the bridge, let's listen to that. >> what i have seen on my own eyes between six and seven people laying down. >> reporter: were they on the pavement when he was zigzagging? >> walking as normal and the first hit, the second people and the third time no one realized it. in and out, zigzag. >> reporter: yes. >> and it was quick, less than ten seconds in between. >> reporter: yes. and then what happened to the car? did he just carry on over westminster bridge? >> the car continued to drive all the way down, the bottom of the bridge there is a bus on the left-hand side, so he just continued between the bus and the pavement. there was over 100 people on the pavement. >> malcolm, a low-tech incident or series of incidents. we don't know about the coordination, who may have

instigated it but we can see the response and how effectively the british do respond to situations like this. we also are being told the london eye is tweeting they are on lockdown so there are passengers stuck on the ferris wheel waiting to released and they are staying on lockdown as a precaution. malcolm, let's talk about the coordination and what probably happening at the nctc, at the counterterrorism center in virginia. >> sure, in the united states, the cia's national counterterrorism center, they are on 24/7, 365 watch, and they monitor all media, all social media as well as their intelligence collection assets and resources in england, it would be leesayson officers, defense attaches, anyone with a mobile device or their coordination offices that they have over there as well, and they would be getting every bit of data that we have in right now. they're watching this program, as we talk, because you never know where you're going to get that little scrap of information, like that gentleman

talking about the car zigzagging up and down the bridge. we didn't know that until just now, running into 100 people. that's a very critical part of the intelligence. first off, because you need to know what happened, how did this incident manifest itself? second, is there another incident which may be unfolding as another plot in another country, like the united states? so that allows us to give protective organizations, protective teams and law enforcement key initial intelligence, in case this is, you know, suicide vehicle, weapons system day, all around the world, right, where numerous cars may be doing this or numerous people may be inspired. all of this goes to the nctc. they dispatch this out to homeland security, department of defense, and all of this is melded together into a knowledge package which as i said is shared throughout the world. >> and by the way, just to your point, nypd says that they are dispatching teams around british

sites, around new york city, the consular site, presumably the u.n. mission so extra protection for potential british targets here as well, even absent any hard intelligence. we also note that boris johnson was not at the class photo. i know he went to the state department today after a meeting in the white house this morning, and then presumably when this happened, probly wt into an office or back to the embassy to at least consult with home base. theresa may, just to reconfirm, is at number ten and near number ten downing street is our own bill neely. bill, if you could reprieve what you know now based on reporting from london. >> reporter: yes, so i'm on white hall just up from downing street and maybe 500 yards from where this double incident happened. andrea, this was an attack at the very heart of british democracy, at the very heart of the british state. i'm near downing street, i'm

right beside britain's ministry of defense building, and this happened obviously all around parliament. we've got unconfirmed reports so far that one woman is dead. that's from the reuters news agency, quoting doctors, but no official confirmation of that, and up to a dozen people injured, and as we've been saying for the last while, this does appear to be some kind of double incident, one involving a car, the second involving a man with a knife. but you know it's a very long time since there has been an incident around the palace of westminster itself. there was a famous bomb attack here in the 1980s, when a conservative lawmaker was blown up by irish republican terrorists. of course with the 7/7 bombings which killed more than 50 people, and a few years ago, there was an attack by a man with a machete on a soldier lee

rigby, who was murdered in daylight in pretty horrific circumstances by one of two men who first rammed him with a car. so you know, london has been used to terrorist incidents in the past. i suppose we've been pushed back several hundred yards and people are braced now and wondering is it over, or is there something more to come? and there are certainly plenty of officers on the streets. they have cleared the area around westminster. i understand people, tourists who were on the london eye, the large attraction close to westminster are still actually trapped in that attraction, but it's fairly calm here, but people obviously remembering the incidents in paris and in other places know that sometimes when there's one terrorist incident, there can be others that follow. andrea? >> and keir, we should note that this is the first anniversary of the terror attack in brussels on

the airport in brussels. >> reporter: yes, that's right. and that attack was marked this morning with very, in a very solemn ceremony, and of course dozens of people were killed in that attack, and ever since paris and brussels, people here have been braced, i suppose, not wondering, not if a terror attack of some description was going to happen, but when, because britain, of course, has been at the very center of the campaigns in iraq and syria against isis, but as we've been saying all morning and all afternoon, this while a low level attack involving a vehicle, a man with a knife, you know, again, police are not underestimating that something even worse could follow, because the pattern of many isis attacks, for example, is that you have a primary attack, then

civilians and rescue crews and police and even troops gather, and that's when the secondary attack happens, and certainly it is hugely significant, where this took place. as i said, this is the very center of british power, within a few hundred yards of where this happened, not only have you got the houses of parliament, the house of commons, the house of lords, you've got downing street, we are reasonably close to where the anti-terror committee, c.o.b.r.a., meets on a weekly and sometimes daily basis and the ministry of defense is close by, so no, you know, it's no coincidence where this attack has taken place. >> and bill neely, it's a five-hour time difference, but it was at the conclusion of question time, so as we talked to camilla earlier, there would have been a lot of people in westminster. it's a very busy time this wednesday, and recess in about two weeks, so they had a lot of business to do.

there were more eyewitnesses who we've interviewed. let's listen to them. >> i heard the crash first, and then i thought it was a genuine accident having gone right across the cycle lane and shortly thereafter i saw somebody laying down beside which again, i assumed that it was a cyclist they'd gone into and i thought oh my goodness. >> we're fortunate to have nbc's keir simmons, normally in london but on duty here in the states right now in new york. keir, you've been talking to your sources. what have you been able to glean? >> reporter: that's right. i've been speaking to british security officials. they are still trying to figure out the crucial question here, which is whether this was one person or more than one person involved. that is crucial, because it will give them an insight into whether this was a some kind of a coordinated terrist attack or whether it's somebody acting as a lone wolf, if you like, inired from abroad. the kind of thing that we have seen has been encouraged, if you like, by al qaeda, by isis, by

both of those organizations, in publications, they have talked about using a vehicle to attack. we've seen it happen in france. we've seen it happen in germany. what i'm told, though, at this point, is they are not certain whether it was more than one person. i think that that helps to explain the kind of accounts that we've had. in terms of what we're seeing, what we've seen, people have talked about a vehicle crashing into the barrier by their houses of parliament. you can see from the pictures there appear to be incidents along the bridge there across the thames. that would suggest that vehicle traveled from the south side of the thames across that bridge towards the houses of parliament. from what i've seen, andrea, it looks as if a vehicle is crashed there, quite close to the corner, with parliament square. that would make it possible for somebody to run around that corner, and then run into the driving entrance, if you like, to the house of parliament. in other words, it could be one person who has carried out this attack, if that's what it is,

with the vehicle, and then has according to reports attacked a police officer with a knife. we don't know at this stage whether it is one or more than one person, and that will be absolutely crucial, andrea. >> absolutely. keir, if you'll stand by for a moment, jeremy bash rejoining us, our nbc news national security analyst. jeremy, if you were at the cia at the right hand of leon panetta as you were as his chief of staff, what would you be doing here if our allies in the uk had just suffered some kind of an attack? >> well, we'd be getting instant updates from cia's own counterterrorism center, as well as the government's national counterterrorism center, down the road in northern virginia, to try to figure out if there are any links at all between these individuals or the biometric information, the fingerprints from the alleged assaants or any other information about the car, the make, and model, the license plate, anything that could

connect this attack, this apparent terrorist attack, with any known chatter that's out there, any information online or that's been put out in social media by isis, al qaeda or any other known terror organizations. i think it's worth noting, andrea, that isis has not conducted many attacks in the uk, in fact, some analysts i'm talking to believe this may be isis, if this is an isis attack, isis' first real attack in london. it also is of note that isis has put out videos featuring up to six brits fighting within their ranks, and in those videos they call for attacks against uk targets, again at this hour, we don't know the authorship of this attack. we don't know the motivation and we don't know whether this was directed by any terror organization, or inspired by terror organization. intelligence officials here in washington and in london and among all of the key counterterrorism partners around the world are resolutely focused on the possibility, the

probability that eyeis continues to want to attack targets in the west so this is a very real serious issue that will be torn apart by our intelligence analysts on both sides of the atlantic. >> how well integrated are our count gerrer counterterror with those in london. i know they're back and forth communication from virginia but presumably we have counterterror officials at the our embassy in london and are they integrated within the metropolitan police there? >> this, closely, talk not just daily but probably hourly on specific threat streams, specific intelligence threads that target the united states and the uk and our interests around the world and at some of our military commands, for example, down at tampa at special operations command, central command, there are british officials who are embedded there because we of course fight alongside british service members in iraq, in

afghanistan, and elsewhere. this is about as tight of a military and intelligence partnership as tight of a counterterrorism partnership as there is among any two countries in the world. >> and we're seeing on our screen now the preparations for scotland yard's briefing, which will be momentarily. you see reporters gathered there behind the orange fence, looks like they've set up microphones and scotland yard is going to be briefing. i should also say the mayor of london, sadiq khan, issued a statement "there's been a serious incident near parliament square treated as a terrorist attack until the police know otherwise." he also said "i have spoken to the acting commissioner, the metropolitan police service is dealing with the incident and urgent investigation is under way. my thoughts are with those affected and their families." the mayor continues "i would like to express mys th thank to police and emergency services who try to keep us safe and show

bravery." for the latest information visit the metropolitan polic police @news.net.police.uk, that would go also for u.s. citizens urged to contact the embassy if they are traveling in london or if they think that they have relatives or friends possibly affected by this. bill, back to you on white hall. bill neely, if you can hear me, i think you're near number ten on white hall. >> reporter: yes, that's right andrea. police helicopter above us, cars going back and forth, some of them certainly containing what appear to me to be plain clothed detectives. one thing worth noting, andrea, this happened in one of the most heavily secured areas of london. i mean, on most days, in fact, every day, really, the palace of westminster at ten downs street are surrounded by heavily armed police, in fact just to my left,

a few minutes ago, we saw troops rather oddly doing a ceremony just a few hundred yards from where this happened, so as i said, behind me is britain's ministry of defense. so heavily secured area, and yet obviously in a low level attack, this man with a knife was able to threaten police officers and someone else in a car clearly has injured a lot of people on westminster bridge. you know, these are the threats of modern day policing and of modern day terror. isis has obviously called for low level attacks for people to use vehicles, to use anything that is at hand, to injure and to kill, and these are the challenges that today's security forces face, but at the minute here, the streets around westminster are closed off as we wait for scotland yard to give us more details. as we've been reporting on --

>> as we've been reporting, bill if i may interrupt you, scotland yard is beginning to brief. let's go to that. thank you. >> although we remain open-minded to the motive a full counterterrorism investigation is already under way. this is led by the counterterrorism command. at this stage i will confirm what we know happened but i will not speculate. we received a number of different reports, which included a pson in the river, a car with pedestrians and man armed with a knife. officers were already in the location as part of routine policing. but immediately additional officers were sent to the scene and that included firearms officers. we are working closely with the london ambulance service and the london fire brigade. i'd like to repeat our request for the public to avoid the following areas -- parliament square, white hall, westminster bridge, lamberth bridge, victoria street up to the junction with brod wei and victoria embankment up to embankment tube stations to

allow emergency services to deal with this ongoing incident. there is an ongoing investigation being led by the counterterrorism command and we would ask anybody who has images or film of the incident to pass those to the police. we know there are a number of casualties, including police officers, but at this stage we cannot confirm numbers or the nature of these injuries. our response will be ongoing for some time, and it is important that we gather all possible information and evidence. public safety is our top priority, and we are reviewing our policing stance across london and throughout the capital this afternoon. there will be additional officers on duty and deployed across the capital. i would like to ask the public to remain vigilant and let us know if they see anything suspicious that causes them concern and if they do, dial 999 immediately. the acting commissioner, greg mackey, is being treated as a significant witness as he was at the scene when the incident started. whilst he is not injured, it

would be inproappropriate for h to talk about the incidence. our thoughts and his thoughts are with all of those involved and responding to the incident scene. i would stress if anyone has information they are urged to call 1800-789-321 and i would stress if the public has any information or seen any suspicion to dial 999 immediately. >> at this stage does the incident seem to be over? >> i'm not going to speculate. we've got, you'l see the response we've got here. officers are responding. i stress that it's our priority to keep london safe. people are going home this evening will see additional officers deployed, armed and unarmed across london in order to achieve that aim. >> reporter: gunshots fired? >> i've told you what information i have and we will keep, continue to keep you updated as we find things out. i am not prepared to speculate. ladies and gentlemen, i'm going to thank you very much for your time here this evening. i would absolutely stress to the

public number one priority working with our partners is to keep london safe. if people have information dial 0800-789-321, but most importantly if people see anything dial 999, if they think it's an emergency. thank you very much. >> you just heard scotland yard briefing with just the barest of information, saying that there are a number of casualties, including police officers. they won't say how many. they're asking the public to help if they have any information. nbc's matt bradley is across the westminster bridge from parliament. matt, what are you seeing from your vantage point? >> it's been very tough actually to get close to the incident and that's xwhy i've been walking around crossing bridges and crossing the opposite bank and so what i'm seeing is swarms of police officers, police vehicles blocking off bridges, and there are multiple bridges here, that are crossing over to the parliament side. and right now, it looks as though people are just sort of flooding out of offices and headed home, a lot of people.

of course are being told to shelter in place but the active office buildings across the river appear to have let people go for the day and a lot of people are making their way home. it's kind of reminiscent of any sort of major crime or terrorist incident, where everybody's just told to remain in place or to evacuate immediately and to just simply head to safety. but it's not really a sense of panic outside of the police course. people are milling about as always and heading back just kind of commuting back home. so we're seeing swarms of police officers on all sides and all of the roads are cut off, but again, most people here you wouldn't necessarily get the sense they're panicked or afraid. they're really just kind of going about their usual day-to-day business. >> that is exactly what we've always witnessed and experienced with our friends and allies in the uk, when they face an emergency, they face it with

that classic proverbial british stiff upper lip. is the tube open? is the subway open? >> i actually haven't heard that. i was just in a shop and people were talking, the man, his credit card machine wouldn't work and speculated to customers there must be something going on, right across the river and right next to a huge amount of police cars, so clearly the word isn't getting out to everybody. so the tube and bus system have been diverted and probably not going to be driving into the closed roads but as far as i know, most of the stuff is still functioning. most of the commuters, rail and tube system as far as i can tell seem to be working. people seem to be heading home as they normally would. there doesn't seem to be a lot of distraction. nobody's asking around trying to figure out how to get home or rushing for cabs. everybody just seems to be going as normal. >> matt bradley and westminster, security analyst joins us from

london. duncan, you heard scotland yard's briefing, the barest essentials, they don't know the incident not yet saying is over. >> that's correct. they are playing their cards close to their chest. i was in the briefing with b.j. harrington who just took that press conference only last week, in which they were preparing an exercise on the thames, in case isis or some other terror group were to launch an attack coming down the river, and now we've seen an attack coming over the river, crossing on a bridge, and it is the kind of attack that they've been prepared for. they've been prepared for vehicle borne attacks. we saw an incident about a year and a half ago in which mi5 and the police managed to crack a plot to run down and execute u.s. servicemen outside their base, and for that very reason, and the reason that they actually succeeded in killing a

british serviceman about three years ago now using the same technique, again, running into individuals, and then using a knife to attack them, the security services and the police here have been very much aware of that threat. the buildings are protected with crash barriers, and armed police, particularly in key locations, like westminster, are ready to shoot to kill. >> and keir simmons in new york, the security while unusual for british standards, is, does seem to me when i visit london, it is less rigorous, shall we say, than the security that we see in washington, d.c., and in some new york office buildings. >> that's true in a sense, i guess, in the sense that traditionally of course the british police are not armed, but in the particular area where this, if it is an attack, which it appears to be, has been carried out, there are armed officers. they're from a unit of scotland yard called so-19.

so-1 so-19 would train for an armed terrorist incident and they would have units in that area ready to respond. so it sounds as if there was a quick response by armed officers, and that isn't surprising. i guess the question really, andrea, is how was this person armed? were there arms, if you like, a vehicle and a knife, or did they have something more difficult to obtain than that in the uk, and again, the reason why we ask these questions is because it will help us to understand what kind of person this is, and whether they are somebody or if they are persons who are acting on instructions from organizations overseas or simply inspired and taking it on themselves to do this. again, the other question being how many people were involved. i just want to go back to that scotland yard briefing, andrea, because they clearlyre still trying to figure out what it is at happened here, so they say

they had calls, talking about a man with a knife, a car hitting pedestrians, and a person in the river. they will be trying to figure out whether those calls were valid, and then whether any of those people, particularly the man in the vehicle, and the person with a knife, were the same people, or if this is if you like a multiple attack. again, that will be crucial and just one other thing that i picked up from that briefing, andrea, it may be coincidental but is still quite striking, they say the acting commissioner was on the scene of the incident when it happened, when it started. >> right. >> and was a witness, and that's why that person who is the acting leader of the metropolitan police, the most important police officer in the uk aside from the commissioner herself, that person, that commissioner acting commissioner was there. that will have caused deep alarm in the metropolitan police. they will have been extremely

worried about that, and i am assuming that this was not some kind of an attack that was targeting the actual acting commissioner of scotland yard. seems more than likely a coincidence that officer was there but that is a dramatic piece of news, if that is the case. >> and with that acting commissioner have been in westminster possibly to testify or brief or under what circumstances would someone of that rank be in westminster on a day like today? >> i was just trying to hear what duncan guardham was saying which has deep sources within the british security services and police, and he was talking about an operation that was under way, a rehearsal. i couldn't make out whether he was saying that was happening today, but it may be, there are all kinds of reasons why the acting commissioner of the metropolitan police could be in that area, not least the fact that scotland yard itself is just a few streets away.

all of the key government buildings and parts of the british constitution are there, buckingham palace, the queen is not far away, downing street, just down the street, so there are lots of reasons why he could have been there, coincidentally. >> all fascinating, joining me on the phone is tom mctagie, chief uk correspondent for "politico" locked down inside parliament and a witness to the event. tom, can you tell us what you saw? >> yes, i was working in my desk in parliament, which is overlooking the parliamentary gates where the attack took place, just underneath big ben. we heard a large sort of really loud bang, sounded like a car crash, and then we run to the window to see what was going on, and we heard shouting and screams, and we saw a crowd running past the gates, so we knew something was happening, and then suddenly you saw this

man burst through the open gates, and attack a police offic officer. from where i was, from what i could see it looked like he was stabbing him repeatedly. he then somehow got up and began running forward towards, further into the parliamentary estate towards the entrance to westminster hall, where there are lots of police officers with, armed police officers. they then shouted some kind of warning at him, and then opened fire, shooting at least twice, possibly three times. i can't quite remember, and then that took him down straight away. >> now, how high up are you? how many floors? you had a vantage point, right above? >> i'm probably three floors up overlooking exactly where it

happened. so yes, it was extraordinary to watch. you are watching through a window, as this chaos was happening. you know, we often look out the window and see, you know, marches and protests, and convoy s, going past beeping their horns if there is a specific vote. we see chaos outside all the time, but we've never seen anything like this. >> and when you saw, after the three shots, was he moving? what did you see? did he seem to have survived or did you think that he actually had been killed in this incident? >> from here, it looked like the attacker would be dead. there were shouts and then these shots, probably from i would say ten yards away, the policemen were standing, when he shot the attacker, who then just went down, as i say, very quickly,

and i haven't seen him get up since. i haven't seen him, anyone put a blanket or anything over the top of him, but they surrounded him as soon as that happened, and then they also ran to their colleague, who was stabbed on the floor, who also i haven't seen move, i haven't seen him get up since. >> are you there now, tom? >> they both look to me to not be in a very good state. >> and can you describe the attacker physically? were you close enough to see? >> i'm afraid i can't. i recall that he was wearing dark clothes and was heavily set, but i really couldn't tell you if he was you know, other than being a man, what race he was. >> and in terms of the police,

could you tell what kind of weapons they used? >> i know just from being coming in and out of the parliamentary estate for years they're like a sort of machine gun, they look like a machine gun, but you know, sort of large and not a pistol, but i don't know what was used. i just couldn't, i couldn't say. >> and who is telling you what to do no you're on lockdo? are there officers there telling you to stay in place? >> yes, we had a police officer come into the office and tell us to get away from the windows, because shots were being fired, and then we had an announcement on the intercom throughout parliament saying that the parliamentary estate was in lockdown and we had to remain where we were, and that hasn't changed. >> tom, were politico, thank you so much for your eyewitness account, and a