welcome to bbc news, broadcasting to viewers in north america and around the globe. i'm reged ahmad. our top stories: as the death toll from a dam collapse in brazil rises to 58, with hundreds still missing, there is growing anger at the dam's owner. crisis, what crisis? venezuala's president shrugs off international calls for new elections, as the us delivers fresh warnings to nicolas maduro. ahead of tuesday's brexit vote, ireland rules out changes to the part of the british prime minister's deal which aims to avoid checks on the irish border. and we meet an artist who has gained international acclaim with a little toy piano and some very big ideas. as families continue to wait for news of their loved ones,

rescue teams have resumed their search for about 300 people still missing when a dam collapsed in south—east brazil. 58 people have been confirmed to have died after the dam containing industrial waste gave way, unleashing a torrent of mud. nearby homes were engulfed, in the town of brumadinho, from wherejulia carneiro reports. this is how the mining community in brumadinho looked just two days ago. and this is what it has become. a sea of mud, with hundreds missing beneath it. this could be the most tragic mining disaster in brazil's history. the conditions are challenging for searches. most areas can't be reached on foot. the army say the ground is too dangerous. people here describe a scene of horror as the mudslide engulfed this community. translation: what i saw

was the ground was shaking. trees were rolling and breaking like toys. 10—12 metre trees were like little toys rolling around. hundreds of families have lost loved ones. many others have lost their homes and everything they owned. this wasn't a natural disaster. this is industrial waste from the iron ore mine that provided work for so many here, stored above this community, and held by a dam that gave way. the city's paraopeba river has been tinted by residue from iron ore extraction. mining is the main economic activity here in brumadinho, its main source ofjobs, but now the cause of this unprecedented tragedy, that will mark generations to come. the mining company vale insists the dam was being closely monitored, but prosecutors have already begun moves to freeze the company's assets for damages. three years ago, another disaster took place at another mine in the same state,

jointly run by vale. 19 people died, and the waste from here caused brazil's worst ever environmental disaster. the families‘ sorrow is mixed with outrage. this young lady's father is a driver and was working at the mine on friday. she keeps calling his mobile phone, and it keeps ringing. the country is shocked that this was allowed to happen again, and still trying to understand the scale of this disaster. julia carneiro, bbc news, brumadinho, brazil. earlier i spoke to paulo sotero, director of the wilson centre's brazil institute. i asked him about the history of these accidents in brazil. only three years ago we had a similar accident, a collapsing dam at the doce river, a few hundred kilometres away from this one. it was a major ecological disaster. in that one, the number of deaths was below 30.

in this one, we may be talking about 100—200 people buried in this toxic mud. this was perfectly, perfectly avoidable, and obviously now there is finger—pointing to the company, vale. i think there is also responsibility from probably local authorities, the state authorities. the regulations that do exist needed revision, or they were not enforced, because this dam was considered safe. the risk of it collapsing was seen as low by the company, vale. obviously this assessment was completely and tragically wrong. there will be an investigation into what happened, but we're hearing about a lot of anger from the families, from relatives of people still missing.

do you think that there is some sort of turning point here? it is a turning point, i believe, and i hope it is, in terms of a discussion on relaxing environmental laws in brazil. the government that just was inaugurated a month ago proposed a relaxation of environmental laws. it's not without merit that we have too many regulations. they don't work, and they inhibit business efficiency in many areas. but in this area, of mining, obviously we have a serious problem. we don't need less regulation. maybe we need better regulation, more efficient regulation, that protects industry but above all protects the people, the population in these areas. because this was perfectly avoidable, and that's where the anger is coming from. obviously we don't want to prejudge

what might have gone wrong. but we have a new president in power, jair bolsonaro. is there going to be pressure on him to do something different, perhaps to look at different sorts of safety checks on the existing structures? that is the hope, that he will reconsider some of the changes in regulations. the government response, the federal government response, to the disaster was the appropriate one. they formed an emergency group to respond to the tragedy. he communicated with the nation. but the hope is that, yes, there will be concrete steps taken to avoid a repetition of this. if those steps are not taken, it is sure that in a year, two years, three years from now,

we will be back speaking same thing. this is unjustifiable, avoidable. therefore this is a tragedy, but also an opportunity to correct what is wrong in the mining sector in brazil. the united states has warned venezuela that violence or intimidation against us diplomats or the opposition leader, juan guaido, will be met with a signficant response. donald trump's national security adviser, john bolton, made the remarks on twitter. the political crisis in venezuela is deepening after its president, nicolas maduro, rejected a demand from several european countries, including britain, to hold fresh elections. mr guaido has called for more protests. with the economy in freefall, millions have already fled the country, and thousands are leaving every day to escape violence or just to find food. many pass through the city of

cucuta, on the border with colombia, from where aleem maqbool has sent us this report. through fields and streams around the border, we find desperate venezuelans crossing illegally into colombia. among them is yulet, a schoolteacher, here with her cousin, but upset at having had to leave her mother back home. translation: it's horrible. we're going through all of this just to get a bit of food, because there's nothing in venezuela. there's nothing. as it was, she told us, her monthly salary could onlyjust buy her a dozen eggs. the growing international condemnation of venezuela's president clearly isn't persuading people here their troubles will soon be over. well, many of those venezuelans who have come here tell us the only way they feel their president is going to step down is not as a direct result of the western

pressure, but more something that will only happen when venezuela's powerful military finally turn their back on him. venezuela's military attache to washington, coloneljose luis silva, has abandoned maduro, and says he recognises the opposition leader, juan guaido as rightful president. mr guiado, who just days ago declared himself as interim leader, has offered an amnesty to others who will do the same. but president maduro, who made this rather carefree appearance in a live broadcast on state tv, seems far from worried. he has rejected demands from european countries, including the uk, that he call fresh elections. all the while, venezuelans continue to face hardship. junior helps smuggle people out of the country. "people feel defeated," he tells me. "they don't have clothes or money. they sleep in the open.

they feel defeated." and junior says, in recent days, he has had more demand from people wanting to be smuggled out than ever before. aleem maqbool, bbc news, on the venezuela—colombia border. live now to florida, where we can talk to brian fonseca, director of the institute for public policy at florida international university. bryan, thank you very much for your time. the us national security adviser, john bolton, made that warning that, if us diplomat saw the opposition leader is targeted, that there will be a significant response. what does he mean by that? well, i think what you're saying now certainly tremendous diplomatic, economic and diplomatic pressure, but i thinkjohn bolton and others have gone so far as the essentially say that all options are on the table. we certainly don't know what all options been, but one could

certainly surmise that that maybe includes the use of the us military. if there is some sort of threat of us military intervention, and then the us doesn't carry through with that, if there a real concern here that, if there a real concern here that the us is bluffing? yes, absolutely, and in fact, maybe that's. .. you know, absolutely, and in fact, maybe that's... you know, earlieri absolutely, and in fact, maybe that's... you know, earlier i think we had reporting that 400 russian contractors were on the ground. of course, russia denies that, but there are media reports saying that they are on the ground, that could be part of the attempt to call the us on its bluff. but we will see, certainly, i think those options are on the table, and i suspect that maduro has to tread very likely going forward, particularly when it comes to you as personal on the ground in venezuela. more of an international perspective, we are kind of seeing the allegiances line up kind of seeing the allegiances line up along cold war lines, almost, with russia, cuba, china siding with venezuela. why is that happening? well, aiming, first off, internal... this is a battle between legitimacy and power. you know, the legitimacy

of guaido, largely thanks to the us led efforts to bring a coalition of western nations to support the opposition leader in sort of declaring presidency. on the other side you have power, where maduro still has the loyalty of the military institution. and on that side, of course, the traditional actors that have been supporting the dictatorship of maduro, of course, russia, turkey and china being three countries... cuba, i can't forget cuba, two countries that have doubled down behind the maduro regime. in terms of, as you say it, internally, is the problem here that nicolas maduro doesn't really have a safe escape here, there isn't really a future, perhaps, for him should he step down. yes, i mean, certainly there is no real exit strategy for maduro right now. i know the opposition has made calls to offer amnesty to venezuelan leadership, but there is certainly no guarantee that if there is a transition, but

those that are in the regime now, in the leadership, won't be held accountable. in latin america it is not uncommon for leaders like maduro, dictators like maduro, to either go under hiding, in exile, or in jail, either go under hiding, in exile, or injail, and either go under hiding, in exile, or in jail, and certainly either go under hiding, in exile, or injail, and certainly at either go under hiding, in exile, or in jail, and certainly at maduro heals very comfortable that it is goesin heals very comfortable that it is goes in the direction of the opposition, that one of those two, if not other options, might be part of his fate. right now it appears that the status quo is relatively maintained. we still have the economic crisis, but we still have the leadership there. what could be the leadership there. what could be the tipping point? what is a trigger to change things? well, i think for now the military is certainly the key to either the status quo or transition. where the military leadership or the military institution sits, i think, is probably what we are going to expect in venezuela going forward. now, sort of conventional wisdom or history tells us that the longer this goes on, the more this favours maduro. however, we are starting to see, you know, increased economic pressures . see, you know, increased economic pressures. certainly the back of

london yesterday denying maduro's request of $1.2 billion in gold reserves. and the united states has put the threat of oil sanctions on the table for next week. and so applying that increased economic pressure, combined with sort of a heavy diplomatic pressure that we have been seeing this week, is intended to essentially sort of strike the military into choosing the opposition, moving away from its loyalty to the maduro regime. 0k, it certainly will be interesting to see things go to —— see where things go as pressures build. thank you very much. let's get some of the day's other news: the so—called islamic state group says it carried out two bombings which killed 20 people at a roman catholic church in the southern philippines. the first device went off inside the cathedral onjolo island, in the south of the country, where christians had gathered for sunday mass. a second bomb exploded in the car park as the security forces responded. the attack came days after a majority—muslim area in the region voted for greater autonomy in a referendum. a us diplomat leading talks

with the taliban has arrived in kabul to brief the afghan president on developments during recent talks with the militants. both special envoy zalmay khalilzad and taliban officials said progress had been made during six days of talks in the gulf. there are reports that another round of peace talks has been scheduled in a month's time. do stay with us on bbc news. still to come: striking a chord. the internationally acclaimed musician who's completely out of the ordinary. the shuttle challenger exploded soon after lift—off. there were seven astronauts on board, one of them a woman school teacher. all of them are believed to have been killed. by the evening, tahrir square, the heart of official cairo,

was in the hands of the demonstrators. they were using the word "revolution". the earthquake singled out buildings and brought them down in seconds. tonight, the search for any survivors has an increasing desperation about it as the hours pass. the new government is firmly in control of the entirely republic of uganda. moscow got its first taste of western fast food as mcdonald's opened their biggest restaurant in pushkin square. but the hundreds of muscovites who queued up today won't find it cheap, with a big mac costing half a day's wages for the average russian. this is bbc news. the latest headlines: the death toll from a dam collapse in south—eastern brazil has risen

to 58, as hopes fade of finding the hundreds of others who are still missing. there have been more warnings to the venezuela leader, with washington telling nicolas maduro not to intimidate its diplomats or the country's opposition leader. speak now to brexit and it's another big week at westminster with a significant parliamentary vote on tuesday. the issue of the border between ireland and northern ireland has always been — and remains — one of the biggest causes of disagreement among british politicians. here's our political correspondent, iain watson. could the irish border scupper a brexit deal? in the absence of a wider trade agreement, what is called the northern irish backstop would avoid a hard border here after brexit. but it would also mean the uk as a whole would have to stay close to any eu rules. in what will be a dramatic week at westminster,

conservative mps are likely to make clear they'll only back in what will be a dramatic week at westminster, conservative mps are likely to make clear they'll only back the prime minister's deal if the backstop is time—limited or removed. but the irish government says that would make the outlook for any agreement with the eu decidedly gloomy. listen to what people are saying in europe. the european parliament will not ratify a withdrawal agreement that doesn't have a backstop in it, it's as simple as that. and this government minister expects the eu to change its position when it considers the consequences of no—deal. the whole purpose of the backstop is to avoid a hard border, which risks being a consequence of a no—deal brexit. so the idea that the european union and the irish government would drive this process to a no—deal exit — that is not going to happen. if the government was to ask you to work longer hours and take fewer holidays, that would hardly sound like a vote—winner. but that's what mps themselves have been asked to do as a signal

of the prime minister's determination to push through brexit by the agreed date of 29 march. but there are some influential politicians here at westminster who are pushing for a delay in our departure from the eu, unless theresa may can come up with an acceptable deal within the next month. actually, in the end, someone has to take some responsibility and say, if the prime minister runs out of time, she may need some more time. and that is not about blocking brexit. that is about being responsible, and making sure you can try and get a brexit deal. the prime minister wants to avoid delaying brexit, but she will need a change in the political climate at westminster to get a deal.