welcome to bbc news — broadcasting to viewers in north america and around the globe. my name is mike embley. our top stories: another deadly shooting in the united states. this one taking place at the headquarters of youtube in northern california. three people were injured, one is in a critical condition. the shooter used a handgun and then killed herself. us officials release the list of $50 billion worth of chinese imports that'll be subjected to additional tariffs. and 50 years after the murder of martin luther king, how much progress has america made in tackling racial inequality?

was injured as employees fled into the street. in a moment, we'll get the latest from our reporter in the city of san bruno, but first, here's russell trott. the home of one of the world ‘s biggest social media channels, now itself the focus of world attention. police responded to reports of an active shooter at youtube headquarters at just after 1245. active shooter at youtube headquarters atjust after 1245. as staff gathered for lunch and a patio area of the main building. burials of the scene of the city of san bruno south of san francisco show officers and security staff a p pa re ntly officers and security staff apparently frisking for weapons. no-17 apparently frisking for weapons. no—17 of who was involved or how many and no—one taking any chances. upon arrival, officers noted

numerous people fleeing from the building. it was quite chaotic. we found one victim with an apparent gunshot wound towards the front of the business as we arrived. several minutes later, while conducting a search of the premises, offices located a second individual with a gunshot wound that appears to have been self—inflicted. gunshot wound that appears to have been self-inflicted. a man believed to be the woman shooter's boyfriend is in to be the woman shooter's boyfriend isina to be the woman shooter's boyfriend is in a critical condition. to other women were also shot for she turned the gun on herself. we are incredibly tightknit community within youtube and we feel like a family. today it feels like the entire community of youtube and all of the employees were victims of this crime. our hearts go out to those who suffered in this particular attack and our prayers are with them and their families. the injured have been taken to nearby hospitals. it is not known

whether the dead gun woman was a youtube employee. our correspondent dave lee is in san bruno. what is the latest? the latest that we have been hearing from police in the last few moments is that there are indeed three people wounded in this attack and one of them critically. as we had in the piece just for i came on we understand that the critically injured person, a man, was the boyfriend of the suspect gun a man, was the boyfriend of the suspect gun woman a man, was the boyfriend of the suspect gun woman although when asked about that specifically, police said they did not want to talk about motive just yet. they would update us on that and other matters tomorrow. it has been over five hours in this attack took place and youtube ‘s headquarters are just up and youtube ‘s headquarters are just up the road behind me. not all of the employees have yet been able to leave the building to go home because police are obviously treating it as an active crime scene

and they are trawling through the area where the attack took base, outside inner courtyard lunch area where employees were having their lunch. they are beginning to get some of those employees out so they can finally go home after what must have been an incredibly long and troubling day. for their part, youtube said they were incredibly that impressed with how law enforcement officers responded. they we re enforcement officers responded. they were on the scene within a few minutes of those initial calls coming in. i think we are still get to hear more precisely why this attack took place. any more details attack took place. any more details at all on how the attack developed and how it ended and whether the suspect shootout was a youtube employee? we have not heard any specific detail about the shooter. we know it was a woman which is a rarity when it comes to instances like this, particularly in america. we don't know whether they are an employee. please would not be joined ona employee. please would not be joined on a detailed. what we do know is

that this attack was over quickly. she to have opened fire, wounding three people, taking her own life and by the time police arrived, they arrived at the scene of chaos with people running out of the building, they said, but it did seem that this was the situation made safe relatively quickly. that is all police will tell us at this point. like i say, several media outlets including our partners here, cbs in the us, are saying that law enforcement officials, off the record, saying that one of the critically injured man was the boyfriend of the suspect in the shooting. thank you very much. our north america correspondent peter bowes is following the story for us in los angeles. peter, guns are very high on the political agenda at the moment. what is the wider perspective on all of this? this comes at a time with a huge amount of scrutiny on gun

ownership, gun control, just 1.5 weeks after that huge march and a demonstration in washington, dc involving some of the students from the florida shooting and other cities. there were protests, demanding that more be done to control guns and, sadly, this is just another example of an attack on a workplace, in this case, perhaps not as serious nor is tragic, albeit very serious for those involved, but many people were killed in the school shooting in florida. that seemed to change the mood in america. the big question is whether 01’ america. the big question is whether or not... many questions, really, but will this shooting at a high profile company like youtube, willie change anything? will it change the resolve of certain senators or the president to do something about changing this? there are some questions being asked about a tweet from the nra, i think now deleted,

suggesting that members should rise up suggesting that members should rise up against youtube because some gun videos had been taken off youtube. have you seen any moron back? this refers to a change of policyjust a couple of weeks ago by youtube to restrict videos that included guns and weapons and especially those guns which were due to be sold in the future. that certainly annoyed some people, especially members of the nra, over recent days. it seems quite unlikely that the change in policy had anything to do with what happened at youtube but it is a point of discussion. it is one side of the story. we hear louder voices on the other side saying that this proves, once again, that something should be done in america to put tighter controls on guns. let's quickly round up for you some more of the main news. president putin says he's

agreed with his turkish counterpart recep tayyip erdogan to speed up the delivery of s—400 air defence missile systems to ankara. the deal has caused alarm amongst turkey's nato partners because the systems cannot be integrated into nato's military architecture. in another sign of closer relations, the two presidents earlier launched the construction of a $20 billion nuclear plant. shares in the music—streaming platform spotify are trading for the first time on the new york stock exchange. they initially went on sale at more than $165, valuing the swedish company at almost $30 billion. the commonwealth games will officially get underway on australia's gold coast on wednesday. the prince of wales is due to arrive on behalf of the queen and embark on a seven—day tour of the country. he'll be accompanied by the duchess of cornwall and will also tour the athletes' village. the prince will hold meetings with australia's prime minister malcolm turnbull, commonwealth leaders attending the sporting tournament and present medals to swimmers. the official list has just been released of chinese imports that the united states plans to subject to new tariffs. they target $50 billion

worth of chinese imports. president trump insists chinese intellectual property practices have unfairly harmed american businesses. kim gittleson has more from new york. just two days after china placed ta riffs just two days after china placed tariffs on 128 us product, the united states has responded with a list of its own. running to 1300 separate items, the range of chinese imports that could be subject to additional tariffs everything from biscuit ovens to flatscreen televisions to jet engines. the us has said that it is specifically focusing on china's robotics, aerospace and machinery sector. there will now be a comedown period before the list is finalised and the ta riffs before the list is finalised and the tariffs come into effect. already, several us business groups have said they oppose the tariffs. it's emerged that british scientists at the porton down defence laboratory have not been able to confirm the source

of the poison used on the former russian spy, sergei skripal, and his daughter. they have identified it as novichok, and say the nerve agent is so sophisticated it was most likely state—produced. russia is the only nation known to have made novichok. the russian government has said the comments by the head of porton down are "proof" that claims it was involved are a bluff. the world's chemical weapons watchdog is due to discuss the issue on wednesday. caroline rigby reports. the government has concluded that it is highly likely that russia was responsible for the act against so 93v responsible for the act against so gay skripal and his daughter. theresa may addressing parliament following the attack. the uk government has always lend russia for the poisoning, and allegation moscow has completely denied. yesterday, the head of the defence research centre report on down, said the substance used was so

sophisticated that was likely only a nationstate was to deploy a. and he said that scientists have not verified precisely where it was produced. we are 10096 certain that this is from the novichok family of nerve agents. a military raid nerve agent. we provided that information to the police and to the government and that has been our role in this. it is not for us to advise on who made the nerve agent or where it came from. the kremlin has called on theresa made to apologise. 0f came from. the kremlin has called on theresa made to apologise. of the uk government maintains that russia is behind the poisoning, saying such analysis was only one part of a wider intelligence picture. it is one month since the former spy and his daughter were found unconscious ona his daughter were found unconscious on a bench in salisbury. skripal remains critically ill, his daughter is now conscious and talking. vladimir putin has said he hopes an emergency section of the chemical weapons watchdog in the hague on

wednesday will clear russia of any responsibility. translation: mack according to the international experts, about 20 countries in the world can produce nerve agents like this that it we call for the situation to be studied in every detailed. we have raised at least 20 questions for discussion and i hope this discussion will draw a line under what happened. investigators from the op cw visited locations in salisbury following the attack that it the results of their independent test are expected within the week. stay with us on bbc news, still to come: how new technology is being harnessed to monitor some of the world's most endangered species. the accident that happened here was of the sort that can, at worst, produce a meltdown. in this case, the precautions worked, but they didn't work quite well enough to prevent some old fears about the safety features

of these stations from resurfacing. the republic of ireland has become the first country in the world to ban smoking in the workplace. from today, anyone lighting up in offices, businesses, pubs and restaurants will face a heavy fine. the president was on his way out of the washington hilton hotel, where he had been addressing a trade union conference. the small crowd outside included his assailant. it has become a symbol of paris. 100 years ago, many parisians wished it had never been built. the eiffel tower's birthday is being marked by a re—enactment of the first ascent by gustave eiffel. very glad to have you with us on bbc news.

the latest headlines: at least three people have been wounded, one critically, after someone opened fire at the headquarters of youtube in california. the shooter — a woman — is said to have killed herself. american trade officials have now published a list of chinese imports, worth about $50 billion, to be targeted by additional tariffs. french rail workers have begun three months of rolling strikes, severely disrupting services. fewer than a fifth of trains are running. airline staff, rubbish collectors, and some energy workers have also walked out in protest at president macron's planned changes to public services. he also intends to deny new recruits benefits, such as guaranteed pay rises and early retirement. lucy williamson reports from paris. to protect their future, to protect theirfuture, france's railway workers are turning to tactics from the past. the right to pay rises, overtime and jobs for life as much a part of national

culture as street protests. at gare du nord, they took their messages to the commuters themselves. mr marcon, they say, is trying to break the power of the unions and his government's reforms, a first step towards privatisation. president macron has promised to transform france and there are many boaters who believe the changes are necessary but these strikers are not appealing to the country's economic head, but to its social heart. france's social model, they say, is what makes us french. it is an argument that has worked before. the testis argument that has worked before. the test is whether the country will back them with almost half the rail company's back them with almost half the rail compa ny‘s court back them with almost half the rail com pa ny‘s court staff back them with almost half the rail company's court staff on strike, just 12% of high—speed trains are running today. one in five regional trains. but forms were so crowded that one woman fell onto the tracks. fellow passengers jumped down to haul her up. his sea i really sick

and tired of it, they have the right to strike them not to jeopardise our jobs. stand-off with the rail unions may not do president macron any harm and he is facing competition for right—wing votes but success may depend on whether public sector workersjoined depend on whether public sector workers joined the strike. having been elected to change france, mr gare du nord is gambling that france itself has changed. —— mr macon. —— mr macron. the duke of edinburgh, who's 96, has been admitted to hospital in central london for a hip operation. in a statement, buckingham palace said the procedure had been planned and would take place tomorrow at the king edward vii hospital. the duke has missed several recent royal events, as our royal correspondent daniela relph reports. the police officers at the entrance — the sign that there is a royal patient behind the doors of the private king edward vii hospital in central london.

the duke of edinburgh was driven here this afternoon, ahead of hip surgery tomorrow. there have been few public appearances from the duke in recent months. last summer, he retired from public life. his final official engagement, inspecting the royal marines on parade at buckingham palace. since then, when he has been seen in public, he's generally looked fit and well. here, a brisk walk to church at sandringham on christmas day. and even though his hip problems have been bothering him for around a month, he was seen in early march carriage driving, still a favourite pastime at 96 years old. but any surgery at this age comes with risk. there are certain technical risks, but the good news really is that the risks are rare and in fact, the outcomes are very good, it's a very reliable way of improving people's pain and improving people's function. i think in a gentleman in the mid—90s, clearly there are some anaesthetic concerns but i have no doubt that the duke of edinburgh will be very well cared for in that regard. the duke would usually

join the queen and other members of the royal family for the traditional service at windsor on easter sunday. his absence at the weekend, a clear sign that the hip problem had become more difficult. the queen will remain at windsor, but is being kept informed of her husband's condition. conservationists are experimenting with new ways to monitor endangered species. they're borrowing techniques from astronomers to survey the animals. the goal is developing a system that automatically identifies animal species from their heat signature. our science correspondent pallab ghosh has the details. the heat signature of a group of chimps wandering through their habitat. this is a new way of keeping track of endangered species. a little further along, rhinos snuffling the ground for food. and these baboons can be seen even through the tree tops. currently, conservationists such as serge wich count the animals from the ground. it's a painstaking process and not always accurate. we have too many areas where we don't know how

many animals there are. we don't know where they are. and we don't know if those populations are increasing or decreasing, and that's a real problem for conservation management. here at knowsley safari park in merseyside, serge is testing out a system which films the animals' heat signature from the air. the drone could spot far more animals from the air, but the problem was that the researchers could not tell what they were, especially if they were far away. what they needed was a system that could identify them from the heat they gave off. what serge needed was the help of an astronomer. claire burke uses software that automatically identifies the size and age of stars from the pattern of heat they give off. she adapted it to analyse pictures from serge's drone, and she found that different animals have their own distinct heat pattern. each different species of animal has a unique thermal fingerprint. so they all look different, depending on what species they are.

and because of this, we can construct a machine learning—based algorithm which will tell the difference automatically between rhinos and elephants and giraffes, and this is what we hope to do with it at the end of the day. the researchers have found that their drone system can successfully identify species at knowsley safari park. so they'll be trying it out in the wild next month. if it performs just as well, it will give conservationists the detailed information they need to protect the planet's endangered animals. pallab ghosh, bbc news, liverpool. on wednesday, it is 50 years since dr martin luther king was shot dead on the balcony of the lorrain motel in memphis, tennessee. though legal equality was achieved with the civil rights act, dr king's dream of full racial equality is unfulfilled. african—americans face higher rates of poverty, unemployment and incarceration. clive myrie visited america's most segregated city, milwaukee, to find out more.

martin luther king said there were two americas. one was white, overflowing with the milk of prosperity. the other, black, a lonely island of poverty and brutality. 50 years after his death, are those two americas any closer to being reconciled ? on the face of it, little has changed at the martin luther king elementary school in the midwestern city of milwaukee. 98% of the pupils are black, reflecting the demographic of the local area. so while segregation is now illegal in education, it happens anyway. with liberty and justice for all... fine words, but milwaukee is the most segregated city in america, where there isn't liberty and justice for all. the north and west are mainly black, the south and east, mainly white, and in the affluent suburbs, postal workers are the most frequent black visitors.

academic marc levine has written extensively about the racial divide here. milwaukee, in terms of the level of segregation in the town, is precisely the same as it was 50 years ago. a black household making $100,000 a year has about a 20 times greater possibility of living in a concentrated poverty neighbourhood than a white family. and it's notjust in housing that america remains a land divided, half a century after dr king had a dream. 50 years ago, the unemployment rate was 6.7%. in 2017, 7.5% - still roughly twice the rate of whites. and 50 years ago, just over 40% of black people owned homes, about the same rate as today, yet 70% of whites are home owners. now they're taking everything we had but now we are showing them

we are not afraid of them, no more. housing has always been a racial faultline america. black people have sought and been denied the right to live where they were refused loans for homes. in 1967, thousands marched for fairness in milwaukee. and these people were some of the protestors, demonstrating on this bridge the divide between black and white in the city. the white people with their children and everybody else, their bricks and bottles, name—calling. there was all kinds of things that happened by the time you got to the end of that bridge. old newsreels help jog memories of their sacrifice. that's my mother! that's your mother there? yes. yeah, that's my dear mother. but how much do they think things have changed in america? milwaukee has become more tolerant in where they place the blacks, but they're still doing the same thing, they're segregating us, putting us into different areas, though. i don't care how much money you've got, what you got,

they're looking at this. right. but some are fighting back. a non—profit organisation, the milwaukee fair housing council, has undercover researchers who investigate landlords over racism. i met two of the researchers, one black, one white, who went to the same landlord looking for a flat. they were very, very accommodating to me. they were keen? oh, yeah. yeah, yeah. i was told there was nothing available and come back later. i subsequently went back about a week later and was told nothing was available. that was it? that was it. it's really disheartening to me because it is a symptom for me, of something that is really sick in this society. no matter what i've accomplished, no matter what my station in life, i'm reminded that i'm a black person living in america.

dr king wanted these children to achieve their american dream, and he wanted this country to find its soul. while the level of inequality remains, he remains a voice of anguish for millions. finally, the latest on that breaking story from california. police in california say the suspected attacker in a shooting at youtube headquarters in the city of san bruno, south of san fransisco, is dead. the woman, who used a handgun, seems to have shot herself. three other people are being treated in hospital — one is in critical condition. there are unconfirmed reports that the most seriously wounded person is a former partner of the shooter. police are saying all buildings are now secure. senior staff at youtube have officially thanked the authorities and employees for their help. news of the shooting first emerged on social media. staff tweeting that they had heard shots and were in lockdown. much more on all of the news any

time on the bbc website. think you are watching. —— thank you for. well, wednesday is going to be one of those days where you might look at the sky and just think the weather cannot make its mind up. it's really going to be that changeable from hour to hour. we'll have strong sunshine and downpours as well. some of them will bring thunder, possibly hail and some gusty winds as well. it's all thanks to this area of low pressure. you can see the clouds spinning around here, that's been sitting to the south—west of the british isles over the last couple of days, and finally, that low will be barrelling across the uk. so into the early hours of wednesday morning, already some showers around across a number of western and south—western areas and still, we have the cold air across scotland. in the last few days, throughout easter, we have snow across the northern parts of the uk. we still have the remnants of that cold weather in scotland and it's still with us on wednesday. but to the south, here's that showery low that will be moving across the uk.

so the thinking is that first thing in the morning, some of us will have showers, others will have clear blue skies. it'll already be very mixed first thing in the morning. but let's zoom into scotland first of all because here, we still have the snow. it will be falling mostly across the hills and mountains but in the lowlands, i suppose, there is the chance of some sleet falling here. but to the south, across england and wales, not necessarily northern ireland, but england and wales, lots of showers around. but you can see, it's sort of like peppering england and wales. so very hit and miss. there is a chance that some of us will miss the showers altogether. whereas others might get lots of them. and then you've got the hail and thunder which i mentioned earlier on. now, eventually into thursday, that showery low moves out into scandinavia. you can see here it is, just approaching denmark. we're in between weather systems, and actually a chilly start to thursday. chilly, i think a frost in one of two areas. that's why the temperatures will be a little bit lower on thursday, 10—12 degrees, but then we've got a change on the way for thursday into friday. this low pressure comes in.

so this is another area of weather, cloud and rain out west here. but the winds are blowing out of the south. given some sunshine, we're thinking maybe eastern areas, it is going to warm up again. so possibly getting up to around about 15 or 16 degrees on friday. whereas in the west, where you have the cloud and rain, of course, it's going to be quite a bit cooler. maybe 10 degrees in belfast. towards the end of the week, friday, saturday quite possibly as well, we're still hanging onto some of the milder weather across south—eastern areas. so very changeable weather, i think, over the next few days, but it will improve eventually. this is bbc news. the headlines. police in california say the suspected attacker in a shooting at the youtube headquarters outside san fransisco is dead. officers say the woman died of what appeared to be self—inflicted wounds with a handgun. ——san francisco. three other people are being treated in hospital — one is in critical condition. american trade officials have published a list of chinese

imports worth about $50 billion that could be targeted by additional tariffs — the latest move in president donald trump's simmering trade confrontation with beijing. the list covers more than 1300 separate items. the head of the british government's laboratory at porton down says it has not established the provenance of the novichok nerve agent which was used to poison the russian spy sergei skripal and his daughter. gary aitkenhead said it was not porton down's job to say where it was produced. now on bbc news...hardtalk.