right now at 6:00, two deadly blasts rocked the boston marathon. >> there are deaths and dozens of injuries. >> large plumes of dust, smoke, glass. obviously everybody was going crazy. at first it almost sounded like a cannon blast, but it felt so strong it literally almost blew my head off. two homemade bombs went off near the finish line. >> tonight here in the d.c. area, local police are stepping

up patrols and are on heightened alert. we have live team coverage. good evening. i'm doreen gentzler. >> and i'm jim rosenfield. our top story, terror in boston. a couple of explosions going off during the marathon. >> counterterrorism officials tell nbc news that multiple explosive devices were found timed to go off at the height of the marathon. we're expecting to hear from the president at 6:10 in just a few minutes. d.c.'s mayor and police chief -- police officials are also holding a news conference shortly. we will have live coverage of both. first news4's aaron gilchrist has the latest on what we know right now from our live desk. >> let me start with this talk about a potential suspect in this case. we have been reporting earlier from nbc news that officials in boston are guarding a wounded man at a boston hospital as a, quote, possible suspect. the commissioner in boston saying no one is in custody per se and they are questioning

several people. one of our reporters in boston at our affiliate whdh reporting that there is a heavy fbi and atf presence at brigham and women's hospital. police with automatic weapons guarding the entrance at that hospital. but police are telling us they are not officially holding a suspect in this case right now. we want to explain exactly what we know about thissin dent that killed two people and injured up to 100. i want to start with video from about 2:50 this afternoon. that, we believe, was the first explosion. again, it happened about 2:50 this afternoon right near the finish line, within a few hundred yards of the finish line of the boston marathon this afternoon. there was a second explosion just a few seconds and a few yards away from that, a few seconds later and a few hundred yards away from that.

as we understand it at this point, two people confirmed dead, 100 or so injured after this incident, taken to hospitals all over the boston area. there are reports that at least two of those victims are children. we want to hear some eyewitness reports right now. >> heard two big explosions, large plumes of dust, smoke, glass. obviously everybody was going crazy. at first it almost sounded like a cannon blast but it felt so strong it literally almost blew my head off. and everybody started running the other way. there were a few people running over towards them to help out the injured and there was some really bad, bad injuries. some people were very, very badly hurt. >> one doctor at a boston hospital described people as coming in with traumatic amputations, meaning their arms and legs had been amputated as a result of the explosion that happened. you see aerial pictures that show lots of debris. there are bloodied streets across the copley square area where the marathon was to finish up this afternoon. we spoke to a man from alexandria, virginia, who was in the area about two blocks from

the finish line at the convention centering. here's what he heard as he was in a meeting. >> we heard something that sounded like a cannon, things shook a little bit. and then i'm not that familiar with the boston marathon, so i thought maybe it was just cannons or something that was part of the ceremony, but some of the people that we were with said there shouldn't be any cannons. we looked out the window, smoke billowing out and people running hysterically. >> at this hour people in boston being told they were not congregate anywhere in the city, they should stay home as the police department there and explosives experts are checking every single bag that was dropped, everything that looked like a package that may have been dropped in the area around the boston marathon finish line at this hour. we of course are staying on top of developments there in boston and will have the latest as they come in. i'm at the live desk, aaron gilchrist, news4. let's talk about local security right now, because the explosion quickly sent local police scrambling as well. >> indeed. we're already hearing about d.c. being on a heightened state of alert.

jackie benson is at lafayette park right across from the white house. what are you seeing there, jackie? >> reporter: i can tell you that heightened state of alert is very evident. we have some video that was shot a short time ago by an nbc news crew at the white house. what it shows is that shortly after news of the incident in boston, secret service agents sprang into action here at the white house. they very quickly put up yellow tape and issued orders to evacuate the plaza on pennsylvania avenue in front of the white house. it is my understanding that they did this with a great sense of urgency. >> the secret service came out. they ordered everyone out of the street and then they frantic kael started running up and down the street with the tape and closed everything off. i asked if it had anything to do with the explosions at the boston marathon. they said they don't know, they just got a radio call to do the evacuations and move everyone out of pennsylvania. >> this scene is being reported on capitol hill also, as i

understand, it is a chain reaction. whenever you have something like this happen in a major city, washington goes on a heightened state of alert. i can tell you that very much of what is involved in this alert, we can't see. but you will know there are a lot more police officers here. some of them may be more heavily armed. a lot of it is invisible, but what you can see right now is you can see a secret service agent standing over there at the other edge of the white house. that's the first time i've seen someone back that far from the white house. you can see him standing there and another bike officer on patrol there. this is something that is obviously being taken very seriously and very closely monitored here in the nation's capital. reporting live in lafayette park, jackie benson, news4. >> thank you. again, we are expecting to hear from d.c. -- the mayor and the police chief shortly and president obama, his speech is moved back to 6:19. so to clues now from the

video that we've all been watching this afternoon. joining us is larry johnson, a terrorist expert, former analyst at the cia. as you watch that blast on video, it tells you something. tell us about that. >> it does not look like what would be called an ammonium nitrate explosive. it is likely a high explosive. i double checked with a buddy of mine who is genuinely -- he knows bombs by looking at how the blast goes. he said it was definitely h.e., high explosive. increases the possibility that you can manufacture a high explosive at home called tri-aceta t. e. that's been the signature calling card of the al qaeda groups. i'm not saying that's who this is. but the fact that was was also distributed using either -- whether it was a backpack, cooler put into a box or a suitcase or put into a trash can, you weren't looking at much more than 30 pounds of explosives. it was probably in the 20 to 30-pound range. something that one or more

people could carry easily without drawing a lot of attention to themselves. something like ammonium nitrate, like what blew up the murrah center in oklahoma city, that was a heavy amounting of explosive. with people carrying something heavy, you're going to draw attention to yourself. clearly whatever planted this bomb or the people that planted it were able to do it in a way that did not draw attention. >> we remember from the explosion in atlanta lots of nails and debris deliberately put into explosion. is this -- are we going to hear that in this case or not? >> someone said they found ball bearings at the scene. remember the rush to judgment back then was to blame a man by the name of richard jewellwho ended up having nothing to do with it. the reports earl on end up being wrong in many aspects. there were two explosives. you know it was not a large amount but it was a high explosive. you get the indication of that

by the color of the blast and by the fact you had so many catastrophic amputations of people who were close to the blast. they judge explosion i'ves by the feet per second that they move. the lower explosives like ammonium nitrate will not do as much separation of body parts as we saw in this, sadly. >> larry johnson we want you to stand by for a few minutes if you don't mind. we're going to president obama at the white house now. earlier today i was briefed by my homeland security team of the events in boston. we're continuing to monitor and respond to the situation as it unfolds and i've directed the full resources of the federal government to help state and local authorities protect our people, increase security around the united states as necessary and investigate what happened. the american people will say a prayer for boston tonight and michelle and i send our deepest thoughts and prayers to the families of the victims in the wake of this senseless loss. we don't yet have all the

answers, but we do know that multiple people have been wounded, some gravely in explosions at the boston marathon. i've spoken to fbi director mueller and secretary of homeland security napolitano and they're mobilizing the appropriate resources. i've updated both parties in congress and on kays like this there are no republicans and democrats, we are americans united in concern for our fellow citizens. i've also spoken with governor patrick and mayor menino and made it clear that they have every single federal resource necessary to care for the victims and counsel the families. i made clear to them that all americans stand with the people of boston. boston police, firefighters and first responders as well as the national guard responded heroically and continue to do so as we speak. it's a reminder that so many americans serve and sacrifice on our behalf every single day

without regard to their own safety, in dangerous and difficult circumstances. we salute all those who assisted in responding so quickly and professionally to this tragedy. we still do not know who did this or why. people shouldn't jump to conclusions before we have all the facts. but make no mistake, we will get to the bottom of this and we will find out who did this. we'll find out why they did this. any response -- any responsible individuals, any responsible groups will feel the full weight of justice. today is a holiday in massachusetts, patriots day. it's a day that celebrates the free and fiercely independent spirit that this great american city of boston has reflected from the earliest days of our nation and it's a day that draws the world to boston's streets in a spirit of friendly competition. boston is a tough and resilient

town. so are its people. i'm supremely confident that bostonians will pull together, take care of each other and move forward as one proud city. as they do, the american people will be with them every single step of the way. you should anticipate that as we get more information, our teams will provide you briefings. we're still in the investigation stay at this point, but i just want to reiterate, we will find out who did this and we will hold them accountable. thank you very much. >> all right, president obama saying say a prayer for boston. he is saying the fbi and homeland security, both agencies responding at this hour. he vows that we will find out who did this and why. >> we are still learning details about the double explosion at the boston marathon, but here in washington, metro is ramping up security because of what happened there. >> we're learning that all day shift patrol officers are going

to stay on duty through this evening's rush hour. adam tuss is joining us live in southwest tonight with the latest on this. adam? >> reporter: hey, jim. first of all, we should tell you that metro says there has been no specific on credible threat against the transit agency. you should know that right off the bat. you can see that the rush hour has not been interrupted tonight, people still coming and going. but tonight there will be more eyes watching. almost as soon as word of the boston blast spread, extra metro transit police officers started fanning out across the system. canine teams checking out the nooks of the station. again, no specific or credible threat against the metro system, this extra presence out of an abundance of caution. riders understand the extra presence and say it's just a part of living in the nation's capital. >> it is definitely scary, but i've been scared since i got here just because i know what it's like in the city. >> i refuse to live my life in fear.

that's -- i'm going to do what i'm going to do. >> now, again, the plans are to keep the day side metro transit police officers who would have normally gone home by now on through the rest of the rush. back here now live, again, no specific or credible threat against transit agency tonight. we'll continue to monitor things as people make their way home tonight. reporting live, adam tuss, news4. >> thank you. some witnesses we've heard from today say that today's explosions are bringing back memories of the september 11th attacks. >> one of those witnesses is amy broadski who was in lower manhattan on 9/11 and saw people falling from the world trade center towers. today she was on boylston street in boston and she told me over the phone about what she saw and heard. >> so there were a lot of people on the streets crying. there are a lot of people that obviously saw it. there are a lot of people that didn't and had no idea what was happening. so i think it was just very,

very, very scary for people to hear this boom from all over the place and not know exactly what happened. >> that's amy broadski who now lives in boston. we want to let you know about several resources for people who may be trying to get in touch with family and friends in boston. google has launched boston explosion site at finder@google.org/personfinder. red cross has a similar service at red cross.org. you can also post information to confirm your own safety or the safety of others you know in the area. boston's mayor has set up a hotline and that number is 617-635-4500. the boston marathon is one of the best-known races in the nation and attracts runners from all over the area. that includes people from this area. jay harrison is a runner from our area who was in the boston marathon today and dan hellie is here with more about his story. >> we're going to go to him on

the phone. is jay harrison on the phone with us? >> yes, sir, i am. >> so you just finished this race ahead of this explosion. tell us what you saw and heard, jay. >> yes, sir. i finished the race at 1:35 in the afternoon and had proceeded down the street several blocks. these are large city blocks, mind you, to the gear check pickup for belongings as we often do finishing a race. it was about a quarter to a half mile away. i had ducked down a side street to go to the men's changing tentent to change into my street clothes. while i was in that tent, at that tent location, i am out of visual line of sight with the finish line. while i was in there, we heard two back-to-back very loud noises that people remarked in the tent that sounded like a very large -- >> jay. jay, can we -- we need to interrupt you just a moment. mayor gray and the police chief

are starting to speak. we'll get back to you shortly. thank you. >> you've been monitoring the situation in boston and any possible consequences in the wake of the consequences there and any possible consequences to us since shortly after this occurred in the city of boston. we have assembled our entire public safety team with me here and we've continued to discuss to the extent that we know anything at this stage any responses that we might make. we don't know of any information that would suggest that there is a specific threat or any credible information around targets here in the region or certainly here in the district of columbia. we're currently implementing those preliminary plans that are part of our ongoing safety preparedness and our safety

readiness. i certainly am sure you understand that we can't go into any significant detail ourselves at this stage about specific response actions and deployments, but we believe that we are well prepared to be able to defend the 632,000 people who live here and the many thousands of people who visit this city, especially during this time of the year. i do want to take this opportunity to remind all of our residents and all of our visitors to the city to remain vigilant, and if you see something, say something. if you see something, please report it by calling 911 or the metro transit police at 202-962-2121. i think everyone knows that we're keenly aware of, you know, the potential consequences of these kinds of terrorist acts and the tragic consequences that

are imposed upon victims of such situations. and want to be able to assure people as best we can that we are at the ready, that we are ready to respond and will continue to gather information and analyze that information as it becomes available to us. so with that having been said, we'll open it up for any questions that you may have and i'll employ the team behind me as the need arises. >> it was a local holiday, a scenario not all that different than what's going on in boston. what do you say directed to the people that plan to come down here? >> well, we have no changes and plans at this stage, bruce. we hope people will continue to come down and engage in this important celebration, the 151st

celebration of the emancipation of slaves in the district of columbia so right now we plan to go forward. >> in the details has there been any threat -- [ inaudible ] >> there is no -- no specific threats. nothing that we have that is tied or could be tied to this, no. >> chief, what are your officers doing that they don't normally do as a result? >> i'm not going to get into specifics obviously, pat. we do have a plan in place to enhance security around the city. we would do that any time there's an incident anywhere nationally or internationally until we have enough information to feel very comfortable that there's no potential connection here to washington, d.c., or threat to washington, d.c. so you will see visible increase in presence. there are some other activities that we are involved in that i won't get into, but i would say for washington, d.c., because we have so many events here and because this is the nation's

capital, the combination of law enforcement resources here on a daily basis, you know, with the united states park police, metro transit police and all of our other partners around here working so closely together, we have a lot of assets and a lot of resources here. everything that needs to be in place is in place. >> and again, chief, what did you tell people of the city to do tomorrow? >> come down and enjoy the events. we have a very strong security plan in place. we are the nation's capital so we do that on a regular basis. we will have some enhanced security that probably some will, some will not be visible to the people who come down, but i want people to feel comfortable to take public transportation, come down to the events and enjoy yourself. we feel very comfortable it's going to be a safe event. >> can you tell me have any streets been closed, any public areas been closed, sealed off, in anything of that sort? >> i think the immediate area of

the white house has been closed off -- >> we've been listening to mayor gray and chief lanier who are saying no information on any credible threat tied to the washington, d.c. area. i want to check with katie davis, who is with our nbc station out of hartford. katie, are you there? >> reporter: jim, hi. yes, we're here live along the marathon route. things still a bit chaotic here. at this point all of the injured people have been taken to hospitals nearby, but all the streets remain shut down as local police as well as federal investigators begin the investigation tonight. we have some video we want to show you of the moments just after the blast happened. terrifying for people running the marathon, spectators, anyone who was in the area at that time. again, two people killed. 23 others injured. many of those people with very serious injuries, amputation injuries. nbc news now hearing from multiple sources that those bombs contained shrapnel and

that that is what led to so many of those serious injuries. back to you. >> that was katie davis reporting from boston. thank you, katie. we were getting some updated information about the number of injuries. we understand now 86 people are injured there at five different hospitals and we believe at least two of those are children. still the death number confirmed at two. that hasn't gone any higher. >> these numbers could change throughout the evening. >> yes. >> we'll keep you posted. of course the boston marathon one of the nation's best-known races. it attracts runners from all over the world. >> a group from our area had already crossed the finish line when the blast happened. dan hellie was able to talk with one of them. >> owen graham, a good buddy of mine from high school. the first thing i did when i heard about this was go to his facebook page to make sure he's okay. he's part of the montgomery county road runners. about 20 runners from the county went up to run in the race. they went off in the first wave, so they had finished a good bit

before the bomb went off. they were in a restaurant telling stories about the race when they found out what went down. >> we've been there for 45 minutes maybe and somebody walks in, a friend of ours, and she tells us two bombs went off at the finish line. so at that point, you know, we have no idea what's going on. >> so do you guys stay there and try to find out more information or do you walk outside to see what's going on? >> at that point, yeah, somebody said, hey, everybody update your facebook, tell everybody you're okay. at that point everybody says can't get a signal. we walk outside marathon officials are saying move away from the intersection, you know, you're hearing sirens all over the place. they're just trying to move people away from the finish line out of the area. we have no idea what's going on.

you know, finally there was a crawl on one of the tvs in the restaurant saying, you know, breaking news, two explosions at the finish line of the marathon. that was -- for a while, that was all we had -- you know, there was no further information. >> what was the level of chaos in terms of where you were, about a mile from the finish line? did it seem controlled? were people running around frantic? did you guys want to stay there or were you worried about a bomb going off in that area? >> some people were more interested in seeing what's going on. there were definitely other people that wanted to get away from the area. i won't say that it seemed -- it seemed pretty organized as far as them moving people away from the area. you know, no one was -- there didn't seem to be chaos, but people were moving with a little

urgency. but where we were, you know, some people felt safe within the building that we were in. but there was others that definitely felt they wanted to move further away from the finish line area. >> so that's owen graham from olney, maryland, finished up about 45 minutes at the boston marathon with a group of 20 or so runners from the maryland road runners club when he was in a restaurant when the bomb went off. so he was five blocks or a mile away so it wasn't nearly as chaotic as it was obviously closer to the finish line. >> but people from all over who aren't familiar with boston, after the blast they didn't know where they were going, they didn't know where their running partners were so it was difficult for people from out of town to figure out what to do. >> everybody in the group of montgomery county runners was okay. >> we're very glad to harry tea. >> thanks, dan. >> thank you, dan. >> now we'll go to our newsroom. aaron gilchrist is at the live

desk with an update on what we know at this moment. >> this incident reverberating around the globe, really. major cities and major transit agencies are on the ready now. they have heightened their alert status and are making sure that a heavy police presence is seen in subways and on streets around the globe. again, two people killed after this explosion. two homemade bombs we believe exploded near the finish line of the boston marathon just before 3:00 this afternoon. we're now getting an update, about 86 people reported injured, some of them major injuries, including amputations of arms and legs as a result of that explosion near the finish line there. we also want to let people know that you can go to nbcwashington.com. we have information there. if you know someone from the area who maybe ran the marathon, 170 people from d.c. ran it, some from virginia and maryland as well, go to nbcwashington.com for the latest information about contacting, finding your loved ones. that is the latest from the live desk. now back to you guys. >> aaron, thanks.

of course we'll be tweeting out information as well throughout the evening. >> we will throughout the night. so again, what we know, two explosions at the finish line of the boston marathon. there have been lots of differing reports about other possible explosions. two confirmed explosions. 86 people injured and they are being treated at five different hospitals. two people killed. it's a very fluid situation. there's a lot of chaos. nobody has claimed responsibility for this. >> still to be determined who did this and why. the president vowing this afternoon we will find out who did this and why. >> and here in washington, a heightened state of alert, but the mayor and the police chief ur urging people to go about their normal activities, that they are taking all the necessary precautions to make sure things are safe here in washington. "nbc nightly news" is coming up next with the very latest from the scene. they will have an hour-long broadcast and hope to see you again later on this evening with more of news4.

>> until then, have a good night.

it felt so strong it literally almost blew my head off. and everybody started run get

other way. there were a few people running towards them to help out the injured and there were some really bad, bad injuries. some people were very badly hurt. >> the clock at the finish line read 4 hours, 9 minutes, 43 seconds when the first explosion went off on boylston street. the second a block away. a place of celebration instantly transformed into a scene of chaos. >> everything was normal. everyone was relaxed and happy. the explosion right next to the finish line and then another 30 seconds, another explosion and then pandemonium struck. >> now there was a race of a different kind. two rescue people. >> i was carrying somebody who lost both of their legs in the explosion. there was a lot of them who lost limbs, catastrophic.

>> ambulances took 19 victims to massachusetts general hospital. >> this is like a bomb explosion that we hear about in the news in baghdad or israel or some other tragic point facing the world. >> it was carnage, it was just carnage. there was a man who lost part of his legs and then all of the folks from the marathon were tweeting the runners, obviously had to get called into action. >> some 27,000 runners from 96 countries signed up for the 26.2 mile race. those still on the course after the explosions were diverted away from the finish line. authorities would not speculate on whether this was terrorism. >> we're not being definitive on this right now, but you can reach your own conclusions based upon what happened. >> reporter: the race famous for heartbreak hill, today the site of just heartbreak. tonight every police agency in

the state of massachusetts is second help to boston, as is the federal government. bostonians are being told to stay indoors and if they have to go out to avoid large crowds, while authorities try to figure out who brought to such a violent, deadly end the day that people in boston, brian, of always called the very best day. >> absolutely, thank you very much, anne, for that. about this day in boston,et's go to katie who has made her way up there. katie, as i understand it, there's 15 blocks that are virtually frozen. adds anne mentioned, people have been told to shelter in place and once they do go out avoid crowds, which is pretty tricky on this day, which is a holiday every year. >> reporter: it's pretty tricky in this area. this is the back bay of boston, a popular area. it is a busy area on a normal day. it is chaotic during the marathon in a good way. it's celebratory. the bars are open, people are out. they want to see what's going on. i guess they're trying not to congregate but for the most part it's pretty quiet in this area.

right after the explosion there were streams of people walking the streets. the subways were shut down and since that -- because of that, people had to walk for miles in some cases, to their destination. in fact we're two blocks away from the finish line, two blocks from where those explosions happened. in fact we saw one woman stumbling to this block with shrapnel wounds. nbc has confirmed that shrapnel was a part of these explosions, that's why there were so many lower limb injuries. witnesses reported seeing tourniquets being applied on the raceway. again, back bay is usually a very busy area. the streets are closed right now. there are a number of roadblocks throughout the area. there was a ground stop at logan airport. we had to circle over providence for quite a while before they allowed us to land. as you might imagine, a very heavy police presence out here. the national guard is here and, again, people are just -- they're on alert. they want to know what's going on. the police commissioner has asked everybody to stay inside,

everybody to go home if they can. from what you can tell, although there are people out here, most of them have heeded that order, at least around here. >> katy, we can see the digital seems to say this was the 4:09 finishing mark. if you're crossing the finish line in this race, you've done very well. to finish at all you've done very well. but people thought, and you can't blame them for this, that this was some kind of cannon, some kind of planned thing. and i had one eyewitness today describe it in terms of world trade. that once the second building was hit that day, we knew it was something different. well, to him once the secondary explosion went off, they knew it was not an accident of the construction of the city like a gas main. >> reporter: certainly. when you're at a marathon, especially up here in boston where they haven't had issues like they had in new york, nobody was expecting something

like this to happen so initially nobody thought -- they weren't sure if it was even -- if it was even -- if it wasn't an accident, if it wasn't a gas main break. people didn't know what was going on. once that second explosion happened about 15 seconds later, people started to believe there was something fishy going on, something bad and that's when people started to get a little scared, started to run away, a bit of a chaotic scene out there. brian? >> katy tur on the streets of boston where for a 15-block area people are not allowed. to washington we go. our justice department, pete williams, has been working this story all day. pete, what can you tell us tonight? >> reporter: brian, tonight authorities confirm there were two bombs, we know that much, but it's unclear how many others were planted. there were other suspicious packages. the word of another bomb elsewhere placed at the jfk library is apparently turning out not to be true. at least five other packages have been found on the street,

have been deemed suspicious and are being destroyed, but this is no firm confirmation of whether they were actually explosive devices, although some officials tonight say there is reason to think that some of them were. we're told, by the way, that one of the two victims that was killed in the explosion was 8 years old. boston police say there was no specific intelligence warning of any kind of attack, and federal officials tonight say there is no reason to think that this is part of any larger threat. at this point they believe it is confined to boston, but a meeting tonight will decide whether any kind of national alert will be sent out. there is no suspect in custody, authorities say, but some people are being questioned, including some with injuries who were taken to boston hospitals. one of those, a person in whom there is some interest, is a young person who was here on a student visa. brian. >> all right, pete williams in our washington newsroom. we'll be looking for further details from there. pete, thanks. michael lighter is our national security analyst at nbc

news. he's the former director of the national counterterrorism center in washington. michael, two things. to overseas veterans of our dual wars these past ten years and those of us who have spent time over there, number one the primary explosion and then the secondary explosion as people are running to the first and, number two, the nature of these injuries. an explosive device apparently with added shrapnel and that kind of haunts everybody involved. >> yes, brian. the idea of using two explosive devices, the first charge which attracts to some extent the first responders, the police, fire, medical and then to have a second charge go off that is potentially targeting those responders. it's potentially the sign of a more sophisticated attack. and as you noted, the shrapnel, the idea that there could have been ball bearings or something else in these explosives clearly specifically trying to kill or maim, not just trying to have a

small explosion and get some attraction, it's the sign of a terrorist organization that's trying to kill people. >> michael, here we are in the post-9/11 era. while it's familiar now to us in a kind of hideous way, it also isn't. we should emphasize that while people, especially in big cities and especially on the east coast are going to see precautionis a train stations and airports and big obvious movement of law enforcement, there is no reason to fear that this is any, at this hour, part of any wider plan, correct? >> that's right. people should view the precautions that they're seeing in major cities, washington, new york, san francisco, los angeles, merely as precautions. and this is exactly what the federal government and states and cities prepare for in the event of an attack. heightening basic preparedness, putting more police on the scene. that is not because they know something specific, it is because everyone wants to make sure that there is a show of

force and should something else arise, that they're in a good position to respond. but it's not the sign of a specific threat necessarily. >> michael leiter in our washington bureau. thank you, as always. across town we go to the white house. chuck todd was in the briefing room when the president entered about 6:10 p.m. tonight to give his remarks on what the white house was comfortable saying so far. chuck. >> reporter: i can tell you this, brian. one of the things the president did not say is he did not call this terrorism. this is, i can tell you from talking to sources, this was discussed and the decision was made not to have the president use that specific word. a national security official does e-mail and says this, to clarify, any event with multiple explosive devices, as this appears to be, is clearly an act of terror and will be approached as an act of terror. however, we do not know yet who carried out this attack and a thorough investigation will have to determine whether it was planned and carried out by a

terrorist group, foreign or domestic. so they're being very careful with their language. we know the president has been briefed all day from the fbi director. now his homeland security director, his own chief terrorism adviser. he himself has been giving briefings to the leadership in congress. i can tell you in talking to officials around here, brian, there's a little bit of a frustration of how little they do know at this point in time, which is why the president was clearly being very careful with the language he chose to use. >> all right, chuck todd at the white house. thanks. we'll take a quick break. when we come back, we'll talk about the nation's need to secure large public events and how that job might have gotten tougher today.

we're back tonight. this is the scene as it happened 2:50 p.m. in boston during the marathon. there's the explosion. one runner hit by shrapnel goes down.

but this is an important point here. between the point of the explosion and the crowd, police, boston ems, race volunteers were caught up in it. they were among the targets. so having seen this, having witnessed this, the question becomes how can we ever keep our public events safe if someone was allowed to get two devices this close to this classic a day in boston, massachusetts. nbc's tom costello has been looking at this conundrum for security personnel all day. tom, good evening. >> reporter: hi, brian. we very often talked about how security changed after 9/11 but security experts have been dealing with terrorist threats at big gatherings since the munich games in 1972, trying to ensure everyone's safely is a herculean challenge. for any police agency, planning for high-profile events with big crowds means months of nightmares. but securing and ceiling a 26-mile course like the boston

marathon with 20,000 runners and half a million spectators is an almost impossible challenge. bill bratten was the boston police commissioner before leading the nypd and the lapd. >> it is extraordinarily difficult, as you might imagine, that 26-mile route, double that, 52 miles, because you have both sides of the street, most of the security would be focused ond finish line area where the actual bombing occurred. >> reporter: atlanta, 1996. a backpack holding pipe bombs packed with nails exploded in olympic park. two died, more than 100 wounded. it wasn't until 2003 that police tracked down eric robert rudolph. london, 2005, a series of coordinated suicide attacks on the subway and bus system left 52 people dead, 700 injured. the attackers used homemade explosives backed into backpacks. those attacks very much on the minds of the secret service when president obama was sworn in for

the first time in 2009. dan bongino was the lead secret service agent as 1.8 million people packed the national mall and downtown d.c. a potential terrorist could have been hiding in plain sight. >> you can't guarantee anything. all you do in the field of security is reduce the probability at an event like this to hopefully so minuscule that if something does happen your response element afterwards is enough to keep the casualties to a minimum. >> reporter: times square 2010. a car bomb failed to explode and was disarmed before it could hurt anyone. two days later a pakistani american was arrested trying to board a flight to the middle east. but big sporting events like the boston marathon have been viewed as inviting targets ever since 9/11. the marine corps marathon in washington attracts 30,000 runners each year. super bowl organizers are often criticized for too much security at the big game. and securing every possible public event that could invite an attack is simply beyond reasonable. michael leiter was the

counterterrorism director under president george w. bush. >> you can't actually protect all the people at all of these large sporting events or any public gathering. that's the huge advantage that terrorists actually have, that they can look for the softest, least offended area. >> reporter: it is not unusual to see that all trash bins have been removed, mailboxes removed, even the manhole covers screwed down. that's the kind of extraordinary security that you get when you're in a presidential zone. putting in place that kind of security at an outdoor marathon, brian, would really be a whole different matter. >> and again how ironic that this happened in what was the most secure zone along those 26 miles today. tom costello from washington tonight. tom, thanks. we'll take another break. when we come back, an eyewitness to today's bombing. the grief was staggering. one hundred days after us senate starts to act are coming together background checks the second amendment hands of dangerous criminals. ninety percent of america background checks. urge them to join comprehensive background checks. demand action. now.

we are back tonight, this day of the twin bombings at the end of the boston marathon. we want to talk now to an eyeness, someone we spoke to earlier during our developing live coverage. sudar azturk was very close to the initial and the secondary bomb. tell us how far you were away, what you remember, what you saw and what you felt. >> i was about a half a block away from the scene. i initially felt the first one and i felt it go through my legs, into my chest. i was sitting down. everyone in the room, everyone outside was -- just stopped moving and instantly had no idea what was happening until that second bomb went off. that second bomb you felt just as much, you heard just as loud and everyone instantly knew that it was not -- not what we thought and it was -- it was a bomb. at that very moment, i walked outside, i looked down the street and you could see smoke

coming. people's faces instantly changed from smiles to tears and fear and were basically running for their lives. you could look at any direction at any moment at the intersection i was and there were thousands and thousands of people that you could see in any direction going down the street. >> if there was any blessing, sudar, it was that the medical tent was right there at the end of the race. you had medical professionals and boston pd already on the scene. >> yeah. i'm staying at the fairmont and the medical tent was right outside our front door. it was one of the craziest scenes i've ever seen. everyone was rushing. no one knew what to do. most of the people were running away. you know, the ems was just running towards the scene. nobody knew what to do, what was happening. everyone was just in fear. >> also the definition of terrorism. it's the last thing you expect at the finish line of the boston

marathon on patriots day in boston. after a wild day, thank you very much for helping us report this story. another break. we're back with more right after this.

patriots day is supposed to be a great day in boston, instead this day turned into a horrible day. katy tur is on the streets of boston tonight. katy, what can you tell us there? >> reporter: the runners are making their way back home, making their way back to their hotels. families of reuniting with loved ones trying to see if everybody is safe, being glad so many are safe and also trying to get their head around just what happened and all of the tragedy that unfolded. again, we are in the back bay of boston. this is a very popular area. after the marathon right about now, this area would be crowded. it is right now pretty dead. people are -- it is very far from normal, brian, and it will be very far from normal for quite some time. >> katy tur in boston tonight. katy, thanks. that's going to conclude our regular half hour of "nbc nightly news" tonight. if your station is carrying it, we will be right back on the air with a special hour-long edition, a second half hour of

the broadcast. if not, it will be available on our website and an early heads up, we're back on the air tonight 10:00 p.m. eastern, 7:00 on the west coast with a