welcome to bbc news, broadcasting to viewers in north america and around the globe. my name is mike embley. our top stories: clashes in the venezuelan capital, as protesters attack armoured vehicles and police use rubber bullets and teargas. our reporter is in the thick of it. both sides have called for a mass mobilisation, as a way of trying to influence the military, and these protesters are targeting an airbase right in the heart of caracas. the us attorney general is grilled by a senate committee on the mueller report, but refuses to testify to the lower house. the british prime minister sacks her defence secretary, accusing him of leaking security concerns about huawei to the press. double olympian caster semenya loses her case against athletics‘ governing body.

to compete, she will have to reduce her testosterone levels. a day after president maduro said he had stopped an attempted coup, there have been more clashes in the venezuelan capital. protesters attacked armoured vehicles with stones and petrol bombs. police responded with teargas and rubber bullets. the crisis appears to be locked in a stalemate. and that is increasing tensions between the united states, which backs the opposition, and russia, which supports nicolas maduro. the opposition promised to make this the largest march in venezuelan history, and the country's future could well be determined by whether that prophecy turns out to be true. tens of thousands answered the call to protest —

proud patriots, some who looked like caped crusaders, angry their beloved country has become a failed state. "we must stand firm", shouted this man, "with the conviction we'll gain freedom". and demonstrators such as businessman carlos gonzalez vowed they would keep on taking to the streets. we are looking for the freedom of our country. that is the message. we've got to do everything we can to get the freedom. that is the most important, today, tomorrow, and forever. in the midst of these crowds, the opposition leader, juan guaido, desperate to keep up the momentum. but his call yesterday for military leaders to switch their allegiance appears so far to have backfired. "we need more military support," he admitted. soon the march became a confrontation, this highway that cuts through the middle of the capital, for a second

day, the battlefield. both sides have called for mass mobilisation, as a way of trying to influence the military, and these protesters are targeting an air base right in the heart of caracas. the authorities were determined to hold the line, and so far, they haven't been overwhelmed. what we are witnessing here is a battle for hearts and minds, and there haven't yet been the defections from the military that anti—government protesters were hoping for. on national television, president maduro last night claimed victory, flanked by the military top brass. his hopes of remaining in office depend on keeping them at his side. on international workers‘ day, this socialist president summoned his supporters onto the streets, and for now, at least, most of those in uniform are obeying his commands.

and this crisis notjust a test of president maduro‘s ability to cling onto power but a test of president trump's influence in the americas, and there is clearly frustration that maduro has not gone already. they thought he was going to go yesterday, they claim there was a plane on the tarmac in to take him to cuba and russia told him to stay put. so how far is russia prepared to go to put its man, juan guaido, in the presidency? the national security adviser welcomed the comments of the military commander who said the pentagon was ready to go in support of the opposition. mike pompeo, us secretary of state, said military intervention was a possibility, but he also said the americans would prefer a peaceful transition of power. the problem is that transition isn't happening at the moment. nick bryant reporting from caracas. the us attorney general, accused by democrats of misrepresenting the findings of robert mueller‘s report on russian election interference, has said he will not testify before

thejudiciary committee of the house of representatives. on wednesday, william barr faced tough questioning from a senate committee about his decision to clear president trump of obstruction ofjustice. mr barr dismissed accusations that he had downplayed the conclusions of the special counsel's report to protect the president. he said he had stuck to the bottom line. us judiciary chairman jerry nadler argues that attorney barr had stonewalled congress. the attorney general has the nerve to try to dictate, or the administration has the nerve to try to dictate, our procedures. it is simply part of the administration's complete stonewalling of congress. and what the ranking member is saying is that, by determining how we'll proceed, we are stonewalling, as if it's our choice that he should not come. he is trying to blackmail the committee into not

following what we think is the most effective means of eliciting the information we need. earlier i asked our washington correspondent chris buckler where all this leave us. yeah, mike, we had feisty exchanges today at that senate congressional hearing. but as for the house of representatives hearing, which was expected to take place just hours later, it's now not going to happen. bill barr says he will not be there, he is not going to take part in it, and it seems to come down to this. that was a suggestion from the congressional committee chairman, jerry nadler, who you just heard from, that he wanted him to be questioned — bill barr to be questioned by lawyers, essentially congressional staff, rather than necessarily those sitting on the committee. now, what mr barr and the department ofjustice said in response was that they do not feel it is appropriate for a senate—confirmed cabinet member to be questioned by members of staff rather than elected politicians. and as a result, they say

he is simply not going to appear. but as you would imagine, that has left the democrats absolutely furious. they say that they will issue a subpoena to try to force bill barr, the attorney general, to testify. but it must be said that there was a subpoena to try to get the full, unredacted mueller report, and that deadline passed today, and they still do not have that report. and we do know that mr barr has been less than forthcoming with committees on capitol hill. we know that he, in answer to a question, "do you know what mr mueller feels about what you did, how you represented his report," he said he didn't know. we know now that he had received a report from robert mueller, making it clear he was very unhappy. robert mueller is going to give evidence himself, isn't it? so this has more life in it, potentially. yes, though it must be said that robert mueller, the special counsel, is still a staff member of the department ofjustice. so they will be involved in that decision about when and how

he gives testimony to congress. but certainly, when you take a look at the letter that has now been released, which was sent by robert mueller, the special counsel to william barr about the way he released his findings, it's difficult to conclude otherwise than that robert mueller was extremely unhappy. he said "it did not fully capture the context, nature and substance of the work and the findings." essentially, he was saying that a 4—page summary william barr initially released simply didn't say all that he had found. it didn't really represent his conclusions. and it does give you the impression that bill barr, as feisty as he was today, still has questions to answer. and also, there is also a really big question about what robert mueller has to say about this whole affair. let's get some of the day's other news: united nations officials say about 140,000 people, including many children, have had to flee their homes in north—west syria in the past three months because of fighting. hundreds more have abandoned towns and villages in hama and idlib provinces in the past few days under a government air and artillery offensive, backed by russia.

indian officials have ordered the evacuation of coastal areas as cyclone fani bears down on the country's eastern coast. the storm is currently above the bay of bengal, with winds in excess of 200 km/h. fani is expected to make landfall on friday, and is to roll over into neighbouring bangladesh, bringing heavy rainfall to the region. in mozambique, almost a week since cyclone kenneth struck, with winds of up to 280 km/h, much—needed aid has started to reach remote areas. villages on islands just off the northern coast have been almost completely destroyed. officials says more than 200,000 people have been affected and more than a0 are dead, though the death toll is expected to rise as aid agencies reach more areas. the british parliament has endorsed a motion to declare a climate change emergency. the measure is symbolic, with no direct policy consequences.

but it comes after increasing pressure from the vocal activist group extinction rebellion, which brought parts of london to a standstill recently with non—violent civil disobedience and protests. the security concerns about huawei's involvement in global communications networks have claimed a high—level victim in the uk. britain's prime minister has sacked her defence secretary, accusing him of leaking information from the national security council. the leak revealed that theresa may was inclined to give the chinese company a role in bringing sg technology to the uk, a move opposed by several ministers. here is our political editor laura kuennsberg. wasn't me, he said... absolutely not. ..and then again and again, the defence secretary adamant he had nothing to do with leaking from a secret government committee. i never have leaked anything from the national security council, nor would i ever leak anything from the national security council. do you admit that you're one of the people under suspicion? as i say, never would, never have.

but his boss, the prime minister, didn't believe him. furious at a leak from the national security council last week, theresa may wanted gavin williamson out, sacking him in her commons office this afternoon, and writing in a brutal letter tonight... but gavin williamson is sticking to his story, replying... the now—former defence secretary was one of several ministers who had doubts about allowing the chinese firm huawei to take part in building our 5g network, superfast broadband.

we know that it will be disruptive... sir mark sedwell, the cabinet secretary and the national security advisor, normally in the shadows, believes the evidence against mr williamson is compelling. but friends of the departed minister fear the leak inquiry called by number ten was partly an operation to find the evidence after choosing the culprit. there are calls tonight to bring the police in, to get to the bottom of exactly what took place. he denies it, and he deserves to have his voice heard, and the way to do that is in a criminal inquiry, given that it appears that the law has been broken in this case. confidence in anyone and anything in westminster is limited everywhere. one cabinet career at an end, for now, the government shaky at the helm. there have been violent clashes in paris, where activists battled police during may day

demonstrations. the protesters started fires, broke shop windows, and pelted the police with bottles and stones. at one stage, they attacked a school. the police have responded with tear gas and baton charges. the so—called yellow vest anti—government activists have also taken part in the protests. hugh schofield reports. it was a may day parade organised by trade unions, ta ken over by the yellow vests. and as so often with the yellow vests, it descended into violence. before the march had even got under way, clashes between police and the so—called black blocs, radical leftists who see street demonstrations as an opportunity for havoc. their protest directly targeted president macron. he has made series of moves to placate the yellow vests, last week promising tax cuts

and higher pensions for the poor. but the demonstrators say it is all eye—wash. translation: there's nothing in macron‘s announcements in response to the yellow vests. there's nothing, right now there's nothing. we've got nothing. we came to paris to protest, peacefully of course, and we've been gassed and trapped for a while now. translation: what we want today is for the government to hear us at last, for mr macron to hear what the french people want. time is up taking us for fools, calling us names like "parasite", or whatever. the police deployed massively, and in the end the violence was contained. the government certainly feared worse. but it is a sad reflection on the state of france when this level of street rioting is coming to seem routine. stay with us on bbc news. still to come: remembering a genius of the track. fans mark 25 years since the death of ayrton senna.

nothing, it seems, was too big to withstand the force of the tornado. the extent of the devastation will lead to renewed calls for government help to build better housing. internationally, there have already been protests. sweden says it received no warning of the accident. indeed, the russians at first denied anything had gone wrong. only when radioactivity levels began to increase outside russia were they forced to admit the accident. for the mujahideen, the mood here is of great celebration. this is the end of a 12—year war for them. they've taken the capital, which they've been fighting for for so long. it was 7 o'clock in the morning, the day when power began to pass from the minority to the majority, when africa, after 300 years, reclaimed its last white colony.

this is bbc world news. the main story this hour: there have been clashes in the venezuelan capital, caracas, with police using teargas and rubber bullets and protesters attacking armoured vehicles. more on venezuela now. earlier i spoke to michael shifter of the inter—american dialogue, and i asked him how he sees the situation being resolved. clearly there's an impasse at a stand—off between the effective president, who is exercising control of the territory, nicolas maduro. and juan guaido, who is the president of the national assembly, recognised by governments throughout the world as an interim president. juan guaido has tried

a strategy of mobilising, people taking to the streets and putting pressure, with the hope and expectation that the regime will collapse and the military would flip from maduro to guaido. they have been defections, but that hasn't happened. so the crucial actor is not neccesarily guaido or maduro or the us or russia, but the venezuelan armed forces who have to decide what they're going to do in the situation, what they will do to crush the opposition or they are going to find a way out for nicolas maduro and to look for another government. in situations where the military

is heavily invested in the economy of a country, with the higher ranks are making a lot of money, i suppose we can assume they will go with whoever will safeguard their investments. is that an oversimplification? no, i think that is precisely right. they are very vested in the regime. they have been involved in many illicit activities and so they are hoping this is going to continue, i don't think they see nicolas maduro as the best guarantor of that. they will try to protect their interests and try to exercise some control over the country. the problem is, i think the military is fractured at this point. i think what is required as negotiation and discussion and deliberation within the armed forces to figure out how to do that. clearly, if there is a transition, an eventual transition, you are going to have to face the question of what kind of amnesty or protection would you give to the military who are accused of human rights abuses

and corruption. just briefly, how much are you worried about the us suggestion that military action is possible, and russian warnings of dire consequences? right now that is very unlikely. there's really no support for military intervention in the us. it would be a disaster and i think people are beginning to look at the consequences of that. i don't think for russia, russia is trying to thumb its nose at the united states and i don't think there are signs that it is very serious. the south african olympian, caster semenya, has lost a legal challenge which means she will now be forced to lower her naturally high testosterone levels if she wants to compete in future events. the 28—year—old double olympic gold medalist has a condition which means she has much higher testosterone levels than most women.

she was challenging new rules from the athletics governing body, the iaaf, which they say would ensure a level playing field. on the one hand i think it's a surprising and disappointing decision in part because what the arbitrators have said, and by the way, it's worth noting first that it was a split decision. so it was not unanimous, there was one arbitrator who had a differing in opinion and unfortunately there is no dissenting opinion to understand where he differed. but essentially what they did agree on is that it is a set of regulations that discriminates against women and that that is proportionate and justifiable because of evidence of a performance difference for women with higher natural testosterone levels. but what we don't know

is which evidence this is based on. and that's what we really need to see with the full report, to understand might there be different ways of understanding that evidence or different understandings about human rights violations because these regulations also require women to undergo medically unnecessary interventions to keep competing? and so that may be where the panellists differed in their opinion. it is likely to matter, isn't it, even after caster semenya eventually retires. because although she's unusual, she is not alone. this is not going to be the end of this issue. not at all. this is really the continuation of decades of what have been called sex testing or gender verification regulations and i don't even think this is the end of caster‘s case. the cast decision left in the very last line, a mode of appeal to the swiss high court, there may be other venues for legal challenge. so i actually think far from this being the end, i think it's the beginning of the continued challenge that has gone on in her case.

i'm sure that the legal minds are putting their heads together to figure out what the best route is. just very briefly, if you don't mind, what do you say to the women athletes who have been speaking out today who have more regular levels of testosterone and say, we are trying to protect our sport? right, i think there is a way in which this natural difference is perceived as unfair. but until we know what that evidence is, there is not evidence at this point that there is a performance difference. it's a secondary question to say whether or not it is unfair and that requires us to interrogate how we understand what is fair in sport. so i understand that view, because they have been told that for a long time but i think we need to look at it critically to undo some assumptions that people have about the science of sex biology and the relationship between testosterone and athleticism which is far more complicated than, the higher the level, the better you do.

motor racing fans around the world have been marking the 25th anniversary of the death of ayrton senna. he was killed in a crash at the san marino grand prix in may 1994. fellow driver roland ratzenberger lost his life in a separate incident at the same track the previous day. the bbc‘s tim allman has more. paying tribute to arguably the greatest racing driver of all time. ayrton senna's final resting place, the cemetery in sao paulo. he wasn'tjust a giant of formula i, he was also a brazilian national hero. i came because ayrton senna surely is the ultimate symbol of dreams, hope and victory. he was one of the few

who have honoured ourflag. not far away, at the interlagos track, an event called senna day. there was a fun run and a chance for the next generation to try out their driving skills. also members of his family, were there to pay their respects. i think ayrton has gone past the category of being famous. he now forms part of the myth category which goes beyond space. he is no longer in this dimension, just like gandhi or mandela. i think ayrton reached that level. ayrton senna wasn'tjust a racing driver, he was a force of nature. three times he was world champion, how many more titles might he have won had he not died so suddenly? and what a tragic weekend that was for formula i. with the austrian driver, roland ratzenberger, killed in a crash during qualifying.

both incidents happened here at imola, where big crowds turned out 25 years later. many of these people probably never saw ayrton senna drive, but they know of his legend. we just have time to bring you one final story. a small ink sketch of a bearded man has been identified as one of only two known portraits of leonardo da vinci. it's thought to have been drawn by an assistant not long before the artist's death exactly 500 years ago. the sketch is part of queen elizabeth's art collection held at windsor castle. it's due to go on display in london later this month. and you can get in touch with me and most of the team on twitter.

i'm @bbcmikeembley. hello. we are now over halfway through the working week, for many there is a bank holiday weekend to look forward to. the weather managed to behave itself but more on that in just a moment. yesterday we saw some showers across the uk, if anything, today the showers, more widespread. and some of them are likely to be fairly heavy affairs as well. it all starts off fairly quietly, there will be a few showers across eastern england first thing, some feeding into wales and the north—west of england. but as the morning wears on, and the sun starts to warm up the atmosphere little bit, we will see some towers of cloud building and then the chance of thunderstorms

increases come the afternoon. we could see a shower just about anywhere, really, on thursday. not all places will see them, but if you are caught in the showers, chances are they are going to be quite punchy. the greatest risk of thunder, i think probably across the midlands and northern england. the rain you see across scotland is slightly different, there is more cloud here, this is actually a weather front. and this is quite a big marker for the change in our weather as we end the week and get into the weekend. the showers will clear overnight, thursday into friday, ahead of this front sliding south. not bringing much in the way of rain but the blue triangles give you the clue, it's a cold front coming in behind it, much colder air on friday. the showers coming in on the northerly wind into scotland. wintry across higher ground, that wind will feel bitter as it strengthens down the north sea coast. ahead of the front to the south, not too bad, some sunny spells, there could be the odd shower, but a high of 15 degrees. to the north, factor in the wind and that seven in aberdeen, probably will feel more like freezing. what a difference after temperatures in northern scotland were 20 degrees

earlier this week. the cold air will dig its way all the way south across the uk through the remainder of friday into saturday. it will stay with us through the bank holiday weekend. that nagging northerly wind could feed in a few showers to eastern reaches of the uk, but on a positive note there will be a lot of fine weather around. away from the east coast, a frost possible first thing on saturday, if you are a gardener or a grower, beware. i've certainly got some of my young plants out at the moment, time to dig out the fleece. for saturday daytime we should see some decent sunshine, but temperatures never really recover. bit more cloud around on sunday, monday the wind should ease and that could make quite a big difference. after a couple of pretty chilly days, saturday and sunday, monday you may find things starting to feel closer to average temperatures for the time of year, shall we say.

this is bbc news. the headlines: a day after president maduro said he had stopped an attempted coup, there have been more clashes in the venezuelan capital, protesters using petrol bombs and stones, police with armoured vehicles, teargas and rubber bullets. there were also pro—government demonstrations. the united states, which supports the opposition, has threatened military action. the us attorney general, accused by democrats of misrepresenting the findings of robert mueller‘s report on russian election interference, has said he will not testify on thursday before a house committee. william barr faced tough questioning on wednesday at a senate hearing. the british defence secretary has been sacked over information leaked from a national security council meeting. the prime minister, theresa may, said there was compelling evidence that gavin williamson was responsible. it is related to security concerns over the chinese firm huawei's involvement in 5g technology.