in yemen's 21—month war. 140 people killed, over 500 injured, in saudi—led air strikes as they attended a funeral. the saudis said the attack was based on incorrect information, and their yemeni partners were to blame. we cross the front line to ask who was responsible. and we follow the bombs back to where they came from — the united states. apparently the united states and united kingdom think it is totally fine for these strikes to keep on happening, and i am just very outraged that we are still assisting what looked just like war crimes. the bombing raised serious questions for saudi arabia and its allies, the us and the uk, about the conduct of the war. could this air strike have changed the course of the war in yemen? relatives and friends are gathering in the yemeni capital, sana'a. they are paying their respects to the victims of the worst air strike in the country's war. there are thousands of people here that have come to mourn their loved ones that were lost in the great hall, and as they are doing that, the saudi coalition aeroplanes are circling above. at today's memorial event, among the mourners are senior figures in the rebel government that controls the capital and large parts of the country. over two years ago, the houthi rebel alliance forced president hadi into exile. a saudi—led coalition, backed by the us and the uk, is trying to put him back in power, and has carried out thousands of air strikes. for the mourners, returning to the burnt—out wreck of the community hall brings back traumatic memories. a month earlier, people were making plans to attend a day—long funeral of a respected senior tribal leader. when abdullah and his youngest son, sadiq, arrived, the building was packed with senior political and military leaders from yemen's rebel government. the funeral had been advertised widely. in keeping with yemeni tradition, thousands of people, most of them civilians, were on their way to attend. one of the coalition‘s key enemies was amongst those expected. rumours swirled that the former president of yemen, now one of the main rebel leaders, was in the funeral hall. minutes before the bombing, an elite security unit that usually only travels with ali abdullah saleh entered the building. until now, it's still not been confirmed whether he was there. we obtained a rare interview with him. also at the funeral were hundreds of civilians from the country's many tribes, who had nothing to do with yemen's war. it was 3.20pm. explosion shouting one of those attending today's memorial event is 14—year—old hussein. hussein's leg was trapped in the rubble. he was desperate to break free quickly. fearing another bomb was going to be dropped on the funeral hall, hussein and his father drew their daggers and cut his leg off. red crescent teams rushed to the site of the bombing as soon as they heard the news. it was a wise decision. a pilot was preparing to drop another us—made bomb. explosion the united states is the main supplier of aircraft and armaments to the coalition. the second 500lb bomb crashed through the roof. detonating inside the hall just when the wounded were being evacuated, and medical teams and rescuers were entering the site. this hall, at full capacity, can take up to 2000 people. now, everyone i have spoken to tells me it was absolutely packed. the first air strike dropped right over here. and as people were running out of the windows, and the first responders were coming in to treat casualties, around six or seven minutes later, the second air strike dropped over here. sadiq's father, abdullah, who had escaped the funeral hall, still believed his son was safe, having seen him flee the burning building. shouting two air strikes on the same target with a gap of minutes between them is known as a double tap. this is often classified as a war crime, as it targets rescuers and medical teams. sadiq was killed by the second strike while searching for his father. he was 26 years old. he had only been married for a month. his death and that of 139 others also allegedly broke other parts of international humanitarian law. it is actually forbidden to conduct an attack where loss of life or injury to civilians is out of proportion to the direct military advantage gained. the hall was a community civilian establishment and the funeral was advertised on social media and on national tv. initially, the saudi—led coalition denied striking the funeral at all. the united states expressed immediate concern, warning that security co—operation with saudi arabia was not a blank cheque. a week later, a saudi—led investigation team blamed an unnamed person in the yemeni military for the strike. it accused the air operation centre in yemen for directing the bombing without obtaining approval from saudi arabia. however, we've obtained a rebel government intelligence report based on mobile phone records and interviews. it says informants were giving live updates of who was arriving at the funeral, suggesting the air strike was preplanned. the saudis have denied that their central command in riyadh authorised the strike. they blame the air operation centre in ma'rib, so i'm going there. i am keen to hear what they say about the attack on the funeral hall. ma'rib is only 100 miles east but due to the war, we need to skirt around the main frontline, a io—hourdrive through the mountains. no western journalist has visited here since the war started. i meet units of the national army, leading the battle to take control of sana'a from the rebels. these forces are equipped and supported by a saudi—led coalition and have their wages paid by them. the key person i want to interview here is the head of the yemeni army. the coalition says its command in saudi arabia didn't know about the attack and blames yemenis in the air operations centre here. but the general has concedes for the first time that foreign coalition personnel in the air operation centre were always present. this raises doubts that it was just the yemenis who ordered the strike on the funeral hall. we asked the saudi government for a response, but they did not reply. the funeral bombing was the first time the coalition admitted a serious breach in its own rules of engagement during the 21 month campaign. but the un ngos and many human rights groups have regularly criticised the way the coalition air campaign has been conducted. to find out more, i'm travelling to a yemeni city that's been bombed the most by coalition jets. and the site of another double—tap air strike. sa'dah is a 150 mile drive north from the capital. homeland of the houthi rebels. the houthi rebels have been accused of regularly committing war crimes since launching their offensive from here two years ago. when the coalition air campaign started in march last year, the city was pounded. this was once sa'dah's busiest market, hundreds of people used to make a living here selling sweets, food, clothes. now it is completely destroyed. they've fled, leaving everything behind. the un panel of experts in yemen found that the saudi—led coalition had seriously breached international humanitarian law in may, 2015, when they declared the entire city a military target, making no distinction between combatants and civilians. according to the united nations, the first wave of air strikes destroyed 1,200 structures, amongst them five markets, a petrol station. 40% of the population here fled. on january the 21st, coalition jets were circling nearby, waiting to strike. a bomb was dropped on a residential area near sa'dah. an ambulance driver was dispatched from this hospital. abdul was the driver. he arrived at the scene of the airstrike in his ambulance. what happened next was captured on camera. as with the funeral mean in sanaa, a saudi coalition plane carried out a second airstrike, just as civilians were aiding the wounded. he picked up some of the injured, a coalition jet was still overhead. his ambulance took a direct hit. abdul and 17 other people were killed in the three airstrikes. 36 were injured. the double—tap funeral bombing in sanaa on the 8th of october was one of thousands of coalition air strikes since march last year. the bombs in the strike all came from one place — the united states. i've come to washington, dc. the united states government has been the saudi—led coalition‘s strongest backer, providing intelligence, logistical and advisory support. billions of dollars of us weapons sales have been approved. after the funeral bombing, the white house announced an immediate review of us support, expressing serious concern about how the conflict is being waged. despite this, we've learnt that the us air force refuelled coalition jets the day after the airstrikes. in a four week period since then, us tankers flew over 87 missions, refuelling 386 aircraft with over 1.7 billion litres of fuel. indeed this is slightly higher than the monthly average support given by the us since the aircampaign again. there's also been growing pressure in congress about assistance. this representative serves as a colonel in the us air force reserves. he's been following the campaign closely. we're flying our tankers with us pilots, we're refuelling these jets of the saudi led military coalition and then they're dropping bombs. but if you look at the law of war in international law, you can be guilty of aiding and abetting war crimes, so if you're in that direct military operation, refuelling a jet that then commitsa warcrime, my view is that opens up the us to great risk and we need to stop doing it. this week the white house released a provisional statement following the funeral bombing. for the first time since the war began they're blocking the supply of precision munitions to saudi arabia, but the refuelling of coalition jets, which only the united states has the capacity to do, will continue. no current us official would give me an interview, but a recently retired senior state department ambassador, who worked in yemen during the first year of the war, agreed to talk to me. i don't believe that saudi arabia is guilty of war crimes and i don't think the us or the uk for that matter is complicit. so you have to be careful about the way you make the assumption that it has to be on the basis of a clear examination and investigation of the facts before you can say that this was in fact a war crime, and intent also has to be there. the funeral hall is set to be preserved as a monument to those who died. the un estimates that more than 4,000 people have been killed by coalition airstrikes. 60% civilians. the saudi—led coalition says this figure is exaggerated. many yemenis hope that the outcry following the funeral bombing would have an impact. the united states is now reconsidering its position. but, for now, the airstrikes and the war continue. yesterday's weather was all about storm barbara, the second named storm for the season. it has been a quiet winter season so far. there is barbara with cloud working into the uk. the strongest winds are in the scottish islands. reports of power supply problems here. transport disruptions as well. into the atlantic our next storm system is forming, this is connor, strong winds to the north of scotland especially on boxing day. the weather watchers had their work cut out enjoying strong winds, being driven out into the bay in lerwick by the strong winds. that is how we start the day. showers and snow in scotland mainly above 200 metres, perhaps 100 metres at times. this is mainly in the hills where we will see that. because of that, we will have icy conditions on some of the roads first thing. england and wales, a lot of dry weather to start the day. a few isolated showers working into north—west england and across wales as well first thing. the further south and east you are the better chance you have of starting the day on a dry note with a fair bit of sunshine. but it will be quite breezy for all of us. through the rest of the day, those gale force winds will bring plenty of showers in. again, they will be falling as snow up in the hills of scotland. a more general spell of rain moving into northern ireland late in the day. turning damp here. england and wales, a mainly dry day with sunny spells. temperatures, 8—11 degrees. colder than that in northern ireland in scotland. the cold air will be behind us to start christmas day. mild air is on the way. these are the temperatures first thing on the big day itself. christmas day, quite windy. a lot of cloud around. this cold front will go south during the day. bringing wet weather for northern ireland, the north of england, and north wales. the south is still quite mild. temperatures, 111—15 in the mildest spots. further north, cold air moving in. that means late in the day some of us could see a white christmas. the chance of getting a bit of snow in the hills of northern scotland. for boxing day, remember connor? i showed you that on the satellite. it is bringing strong winds to the northern isles of scotland where we have an amber weather warning. gale force gusts for the northern half of the uk. further south, quite windy. a lot of dry weather with sunshine. temperatures between 7—8. later next week, the weather should calm down and we will see a return of night—time frosts. welcome to bbc news, broadcasting at home and around the globe. i'm lebo diseko. our top stories: the un security council passes a resolution demanding a halt to israeli settlement building on occupied palestinian land. the us abstains from the vote. anis amri, the man suspected of carrying out the attack on a berlin christmas market, dies in a shootout in italy. the star wars actress carrie fisher suffers a heart attack on a flight to los angeles, but is said to be stable. president putin faces the world's media, and says he is not worried by donald trump's talk of a new arms race.