welcome to bbc news, broadcasting to viewers in north america and around the globe. my name's tom donkin. our top stories: flying over the front line — we have an exclusive report from mosul where islamic state fighters appear to be using children as human shields. there are many civilians still trapped in the narrow alleys. waiting and hoping — parents of missing children in colombia help in the search for their loved ones. among the 200 people killed in devastating mudslides. president trump says the united states would be prepared to act alone to counter any nuclear threat from north korea. as campaigners protest at the unsolved murders of mexico's journalists — one newspaper says enough is enough. selling for the first time in hong

kong for $86 million. and an iconic andy warhol painting of chairman mao has been auctioned in hong kong. the bbc has seen evidence of so—called islamic state appearing to use children as human shields in the battle for mosul. it comes as the militants — are all but surrounded in the old centre of iraq's second city — and there's a growing concern over civilian casualties. bbc persia and producer joe inwood were given exclusive access to iraqi helicopter pilots — flying over mosul‘s front line. here's their report.

far below, a city that was home to two million people. we are flying with the helicopters of the iraqi army as they fight the so—called islamic state. we are now over old mosul, where the battle is at its fiercest, as the last isis fighters, with many civilians, still trapped in the narrow alleys. and this footage, taken from our helicopter‘s camera, shows the challenges the pilots in mosulface. radio it shows armed men walking through a war zone with children. radio military sources have told the bbc this is the clearest example yet of the use of human shields in mosul. on the ground, major osama explains why human shields are effective. isis use the kids so they escape from our aircraft because they know we can't shoot at them.

they escape this way. but many civilians have been killed since the beginning of the war. mohammed is one of the most experienced pilots in the army. he says sometimes he has to trust to a higher power. i ask my god, when i shoot every time, when i shoot the fire, please, god, save the civilians, just kill the bad guys. the battle for mosul is notjust about taking back a city. it is about regaining the trust of its people. every civilian casualty undermines that work and so, the iraqi forces have to take their time. translation: we have two reasons for slowing down. one is the civilians, the second is that we have got to old mosul. it is a difficult part

of the city to fight in, full of narrow streets with small houses. it is ancient and crowded. back above mosul, the pilots circle, looking for targets. they spot a group gathered in an alley. the men have seen us, too. they shoot into the sky. the helicopter returned fire. it is clear why air power has been so vital. mosul is now surrounded but the battle for the old city will come at a cost. much of it paid by the civilians still trapped inside. nafiseh kouhnavard, bbc news. back on the ground, the battle is still going on in residential

streets of the city. one of the challenges is stopping the militants from detonating car bombs. the bbc‘s defence correspondent jonathan beale is in mosul. just building barricades on these streets which have recently been liberated from so—called islamic state. to prevent car bombs, this is one that didn't go around the corner, they managed to kill the driver before he detonated it, but this is just driver before he detonated it, but this isjust a driver before he detonated it, but this is just a few hundred yards from the front line now. we can occasionally hear gunfire from so—called islamic state. now, this is the start of the old city. as you can see, the streets are wide enough to drive armoured vehicles up, trucks. when they get into the old city itself, there are narrow alleyways where they wait be able to drive armoured vehicles at all and the fright in there is going to be much, much harder. president trump said the us is

prepared to act alone to fight north korea. he said, "if china is not going to solve north korea, we will." north going to solve north korea, we will. " north korean going to solve north korea, we will." north korean missile tests are said to be high on the agenda in talks later this week with his chinese counterpart xi jinping. james person from the public policy think tank — the wilson centre — joins me on webcam from washington dc. very good of you to join me. very good of you tojoin me. the article actually outlines what donald trump says. china has great influence over north korea. to what extent is that true? how much it leveraged to china actually have over north korea and became the us actually do anything meaningful with north korea without them?” actually do anything meaningful with north korea without them? i think president trump's statement is in many ways tried to get china to step up many ways tried to get china to step up its game a little bit before president xijinping's

up its game a little bit before president xi jinping's visit to washington. we have long overstated china's ability to exercise political influence over north korea. there is no doubt that china has greater leveraged over china because of its —— north korea because of its —— north korea because of its economic assistance. china has different influence on the potential and it is not willing to use that leveraged to bring north korea to its knees, for example. which is what we want. to force north korea to abandon its nuclear ambition. there is this trust at the basis of the relationship that limits china's ability to really influence north korean policies. china has been overly interventionist in north korea, a sink. —— they say. interventionist in north korea, a sink. -- they say. this is some kind of warning to china before the two leaders meet. do you think it will work and you think china will be more motivated to act after these

words from president trump? one that would hope. there are some reports that in fact china's supposed cut on coal imports are not really put into effect. one would hope that china would in fact take these sanctions more seriously. the us could actually do a lot more. in that, i think the us underestimate its own leveraged over north korea and again, has overstated china's ability to handle the problem. this has been our default policy for the past three decades will stop essentially to outsource the north korea problem to china. the us really needs to do much more. in some senses, this is actually a very sensible thing of president trump to consider at doing more. at the us stepping up its own game.“ consider at doing more. at the us

stepping up its own game. if we look at action, though, donald trump saying he is putting all options on the table but if we put military action to one side at the moment, what else does he have, what other options can he pursue with north korea? our timelines are out of sync if we are going to rely on sanctions. they are uniquely u naffected sanctions. they are uniquely unaffected on north korea because, and this is what we have been relying on, i thought of twin pillars, china's ability to influence and then sanctions. north korea has been living under sanction like conditions since the 1950s. they have essentially self sanctioned which limits our ability really to get the north korean is to come to the table. we use sanctions with iran. the north koreans are willing to let a segment of the population perished, unfortunately, which is the most troubling part. sadly, negotiations, while not

ideal, negotiations are the best option on the road to eliminating their nuclear problem. negotiating a freeze of ballistic missile tests and future nuclear tests. i think thatis and future nuclear tests. i think that is the best option. the military option i would hope is not seriously considered. i cannot conceive of a scenario where seoul is not attacked. thank you very much. rescue teams in colombia are continuing to search through tons of mud and debris for anyone who might have survived the devastating mudslides in the south of the country. more than 200 people have been killed but, with many others injured or missing, the country's president says the final death toll is impossible to predict. the mud engulfed the town of mocoa, burying entire neighbourhoods, and further bad weather is now hampering the rescue effort.

richard lister reports. mocoa is a place of mud and misery. when the rolling wall of water and debris rushed through here on friday night, it swept away houses, cars, trees and people. whole families died here. the painstaking search for survivors is continuing. rescue workers moving quietly through flattened neighbourhoods, hoping for sounds of life in the wreckage. nothing here. with every hour that passes, hopes of finding more people alive diminish. within hours of the deluge, message boards went up, listing the dead and missing. many of those unaccounted for are children. "we are searching for a baby", she says. "a little baby.

we can't find him anywhere". this man has lost his daughter. "i hope somebody has her", he says. "she's called luisa". closest to the river, the streets are now boulder fields, full of people trying to retrieve what they can of their lives. the shock of this disaster is still sinking in. in the worst affected areas, people struggle to find the places where their houses once stood. the rains that caused this flood were unusually heavy, but deforestation upstream played a part, too. emergency teams have been working here night and day, since the river burst its banks. more help from the government is on its way. translation: there are ten water tankers here and ten more are on their way. we are also bringing water purification equipment and generators to ensure there is a clean water supply for the people. for now, though, many people in this town of 40,000 still lack access to power and fresh water.

the homeless need housing. the infrastructure needs to be restored and the wreckage cleared. deep in the amazon basin, mocoa was hard to reach before. now, with roads and bridges washed away, the challenge is even greater. richard lister, bbc news. lucia garcia is a co—ordinator for the colombian red cross and shejoins me now via webcam. thank you forjoining us. such a huge loss of life so far in mocoa. the hope is that we will find some survivors. what hope is there? on behalf of the colombian red cross, we wa nt behalf of the colombian red cross, we want to express our thanks for

the concerned that the international community has had for this emergency. the colombian red cross has deployed 145 volunteers and employees in order to attend the emergency. up until now, the official information given by the colombian government is 210 corpses found. 112 have already been identified. we have 266 wounded, 300 families have been affected by the emergency and approximately 220 missing persons. the colombian red cross has a service called restoring family links and up till now, we have had 326 persons requesting this service. up till now, we have been able to close nine of the 326 cases

of restoring family links. while ours as the colombian red cross, the services we are providing to our communities are health services, psychosocial support and as i said already, restoring family links. we are supporting the government with water purification plants in order to provide waterfor water purification plants in order to provide water for the communities. there are so many homes and neighbourhoods destroyed, let alone the loss of life. where did you alone the loss of life. where did you even alone the loss of life. where did you even begin to start in a situation like this? i hear that roads and bridges have been devastated and now that nightfall has gone, without electricity, what can you do? yes, everything here in colombia is organised by a government unit. we all one of the

relief organisations here in colombia. we are actually very co—ordinated back at the field. the government gives us specific areas that have to do with rescue. that is the way we organise because as you say, there are neighbourhoods that have actually disappeared. 70 neighbourhoods have actually been affected by the emergency. what we do is really give importance to the co—ordination of the field and distribute them in order to the able to facilitate this rescue and to search phase. as i said, while everything is in co—ordination, as pa rt everything is in co—ordination, as part of the international movement of the red cross, we are actually

also co—ordinating with the international federation and icrc back at the field. we are keeping very organised and in co—ordination with every body back at the field. everybody wants to help, everybody is there and we are doing the best we can. thank you very much for your time, lina, our viewers we can. thank you very much for your time, lina, ourviewers arejoining you to wish you all the best. stay with us on bbc news, still to come: tributes are paid to darcus howe — who's died aged 74 — after a lifetime campaigning for civil rights. 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. this is bbc news. i'm tom donkin. the latest headlines: the bbc sees evidence of so—called islamic state appearing to use children as human shields in the battle for mosul. parents of missing children

in colombia help in the search for their loved ones. among the 200 people killed in devastating mudslides. a regional newspaper in mexico says violence against journalists and the lack of punishment for those responsible is forcing it to close down. norte de ciudad juarez said sunday's edition would be its last after a journalist who worked for the paper was shot dead last month. greg dawson reports. the final headline was a simple one — goodbye. above the door of norte de ciudad juarez a black ribbon to mark the murder which has prompted this closure. miroslava breach reported on drug trafficking. she was shot outside her door the government saying for being a

loudmouth. friends and colleagues came together in mexico city to commemorate her and two other reporters all killed in the same month. campaigners claim more than 100 journalists have been killed since 2012. the majority of cases are unsolved. translation: three collea g u es are unsolved. translation: three colleagues have been killed others injured and the authorities do nothing for in a country where journalists are injured, nothing happens. located on the border with the united states, it has for years to come the most violent of city. drug cartels competing for routes across the border. without the protection and freedom they need, it isa protection and freedom they need, it is a story they are not able to tell. in other news for you this hour

in ecuador over 90% of the votes have been counted in the country's presidential election — the electoral council says the leftist candidate lenin moreno is ahead of his right wing rival guillermo lasso with 51.5% of votes. wing rival guillermo lasso with 51.05% of votes. both candidates have claimed victory. the serbian prime minister, aleksandar vucic, has won a clear victory in the country's presidential election. mr vucic said serbs had voted to continue to work towards greater ties with the european union while maintaining close relations with china and russia tributes have been paid to the british civil rights campaigner darcus howe, who has died at the age of 74. the writer and broadcaster campaigned for black rights and against racism for more than 50 years. our correspondent elaine dunkley looks back at his life. in the fight against police brutality and racism, heroes of a struggle were born. darcus howe, a prominent figure in the british black panther movement. in the 1970s, he was arrested, charged with inciting a riot with a group of activists protesting

about police harassment at the mangrove restaurant in notting hill. it was a completely non—event. until you looked around and saw 600 police. and we thought, hell, what's this? at the trial, all nine were cleared. the mangrove nine became a landmark case, exposing heavy—handed police tactics towards the black community. in 1981, darcus howe organised a 20,000 strong black people's day of action in protest over the police handling of the investigation into the new cross fire in which 13 black teenagers died. darcus was a fearless warrior. he helped to establish a tradition of black self organisation to tackle racial oppression. darcus howe, at times controversial and confrontational. you are not a stranger to riots

yourself, i understand, are you? following the london riots in 2011, there was this heated exchange. i have never ta ken part in a single riot. i have been on demonstrations that ended up in a conflict. and have some respect for an old west indian negro and stop accusing me of being a rioter. at the commonwealth institute, an art exhibition is on show. as well as an activist, he was a well—known broadcaster and writer. always formidable and fearless. for more than 50 years, darcus howe was at the forefront of the fight against racism. an andy warhol portrait of chairman mao has been sold at auction in hong kong, to an asian collector. but the piece didn't quite manage to generate the frenzied level of bidding that had been anticipated. our hong kong correspondent juliana liu was there. 80 million...

82 million... at 86 million... and selling for $86 million. sold! when the hammer came down, this iconic painting of chairman mao was sold for $11 million. it was the first time a warhol depiction of the chairman had been offered at a public auction on chinese soil. the price, though, unexpected fell short of its lowest estimate. the absolute star of the auction was this piece by andy warhol. but the sale disappointed, the painting failed to get as much money as the auction house expected. critics say that it could be because the chinese art world is recovering from a crackdown by the president xi jinping. political imagery is highly controlled on the mainland. four years ago, pieces from this series of paintings were banned from an exhibition in beijing and shanghai. the mao pieces were part of andy warhol's most acclaimed works.

he began the series in 1973, after the us president, richard nixon, made a historic trip to china, to meet the chairman. at the time, mao zedong was one of the world's most famous people. the painting was won by a collector in asia, so it is a homecoming, of sorts, for this famous portrayal of a chinese icon by a western artist. juliana liu, bbc news, hong kong. here in the uk, there were mixed fortunes in the annual oxford and cambridge boat races earlier. in the women's competition, cambridge stormed to the finish line in 18 minutes and 34 seconds — beating the record set in 2015 by more than a minute. for the men, oxford made it four wins in five years, beating their opponents by just over a length. look at those guys, absolutely

exhausted. that's it from me. good life. —— goodbye.. good morning. if you like your weather dry and sunny, you were very happy with the first couple of days of april. in fact, we had sunshine topping and tailing the country. just look at this picture from sunday in south—west scotland. a beautiful day here. similar story in the london area, as well, where you can enjoy the spring blossom. it was the warmest place in the country with 17.2 celsius in st james's park. now, our week ahead will be a mostly dry one. just a little bit fresher, though, and i suspect through the night, some chilly nights will come. a touch of light frost not out of the question. high pressure hanging on in there in eastern areas, but out of the west, these are these fronts pushing in. they will not bring significant rain but will bring a change through northern ireland and western scotland, as we go through the morning, eventually into western fringes of wales in the south—west. ahead of it, though, any early—morning mist will lift

away for sunshine. so, by the middle of the afternoon, eastern scotland should cling on to the dry weather, but elsewhere, those weather fronts bringing some showery outbreaks of rain into scotland and into northern ireland. ten or 11 degrees the high. eventually pushing into the west of wales. more cloud, certainly, through the lake district, wales, and down into cornwall. but to the east, we should see highs of 17 degrees inland. maybe if we keep a little bit of coastal cloud cover it could stay a little cooler and disappointing. our weather fronts continue to push across from the west through monday night into tuesday morning. by now, a band of weak spits and spots of rain, really, just pushing into the south—east. but it keeps a fair amount of cloud first thing on tuesday morning. that will clear away into the afternoon. slowly brightening up from the west, breezy with a scattering of showers to the north and west of scotland. high expected on tuesday, though, temperatures in scotland fresher on tuesday, at about eight to 15 degrees. so as we move out of tuesday afternoon into tuesday night, there's some premier league matches. it looks as though it will be a dry affair for all the kick offs.

just that little bit fresher. but all in all, not too bad, if you are going to watch those matches. and a similarfor the scottish premiership — dry, with temperatures over eight or nine degrees is a high. talking of high, stays with us, really, through the middle of the week, building from the south—west. all the while, these weather fronts toppling off the top into scandinavia. a bit of a stronger wind into the far north and a slightly fresher direction, but this does mean a fair bit of dry, sunny weather on offer for many. very pleasant indeed. take care. the latest headlines from bbc news. i'm tom donkin. the bbc has seen evidence of so—called islamic state appearing to use children as human shields in the battle for mosul. it comes as the militants — are all but surrounded in the old centre of iraq's second city

and there's a growing concern over civilian casualties. more than 200 people have died, many of them children, in colombia's southern city of mocoa. the colombian army and emergency services have joined the search operation. but with many others injured or missing, the country's president says the final death toll is impossible to predict. president trump has indicated that the united states would be prepared to act alone to counter the nuclear threat from north korea. in an interview with the financial times newspaper, mr trump is quoted as saying the us could take unilateral action if china did not put more pressure on pyongyang. now on bbc news: the week in parliament.