welcome to bbc news, i'm mike embley. our top stories: us forces are pulled back from northern syria, as president trump warns turkey he will obliterate its economy if it attacks the kurds. but the countdown to a turkish offensive has begun. the pentagon has said that turkey risks destabilising the region and beyond. hundreds of arrests as activists worldwide begin a two—week campaign of disruption demanding action on climate change. a diplomatic drama over a fatal road crash outside an air force base. britain urges the us to reconsider the status of a diplomat‘s wife, who left the uk despite being a suspect. and more moons are discovered orbiting saturn, bumping jupiter off the top spot as the planet

with the most natural satellites. president trump has been angrily defending his decision to pull american troops out of northern syria, a move that opens the way for an attack by turkey on kurdish fighters, long—time american allies in the fight against the extremist group the islamic state, but regarded by the turks as terrorists. mr trump has repeated his warning to turkey not to take advantage of the withdrawal, threatening to decimate the turkish economy if they go what he called off limits. the kurds have been leading the syrian democratic forces and have been key to defeating the islamic state extremists in syria. the kurds have reduced areas under is control to virtually nothing, and now hold thousands of is prisoners and their families. president trump and the government in ankara have proposed a 20—mile so—called safe zone on the border to help the return of millions of syrian refugees currently in turkey. the kurds see the american

withdrawal, which has already begun, as a stab in the back. our international correspondent orla guerin sent this report from the border. a pull—out at dawn. us troops leaving observation posts along the syrian border. washington says only a small number of troops were moved a short distance. but kurdish forces fear they are clearing the way for a turkish invasion. turkey's president was viewing serbian troops today, an honour guard on a state visit, as concerns grow internationally about what he is planning for northern syria. before leaving home, he seemed ready for unilateral action soon.

"we talked to the americans last night", he said. "and we'll keep talking. we have made a decision, and as we always say, we might come suddenly one night." that's a major threat for these kurdish fighters from the sdf, the syrian democratic forces, who have fought street—to—street against islamic state, with help from the us. they have been washington's key allies in battle, but with the us pull—out, they believe they're being thrown to the wolves. they have vowed to resist any offensive and defend their land at all costs. their spokesman, mustafa bali, told us that an attack by turkey risks giving is sleeper cells a chance to regroup, and even retake some territory.

from president trump, a bellicose warning, via his usual undiplomatic channel. just last month, american and turkish troops were carrying out these joint patrols at the border. but now, ankara intends to go it alone, taking the battle to kurdish forces that it views as terrorists and a threat to its security. washington has no intention of getting caught in the crossfire, but there is concern in the us and elsewhere about turkey's next moves. there is a growing sense on both

sides of the border that accountant has begun. france has called on ankara not to take any action that could harm the fight against the islamic group, and united nations humanitarian officials have said they are preparing for the worst. orla guerin, bbc news, on the turkey—syria border. live now to bethesda, maryland, and to michael o'hanlon, senior fellow and director of research in the foreign policy programme at the brookings institution. good to talk to you. thank you for your time. how do you read what is happening? it is the classic how do you read president trump. we all know 2.5 years and that this is an unusual president, to say the least, and he has already made this kind of statement about syria year ago, leading to the resignation of then secretary of defence mattis, and he essentially then reversed course and took mattis's position throughout 2019 up until now. so is he going to reverse himself again? i guess we've

had some movement of us troops today, but those were in small numbers, and maybe they could come back, or at least not continue the process. i really don't know how to read this guy, and i'm sitting here about eight miles from the white house. no, it'sjust one of about eight miles from the white house. no, it's just one of the perplexing presidents. he is reflecting the frustration that a lot of people in the united states and the united kingdom and europe in generalfeel and the united kingdom and europe in general feel about this fight in syria, and about the broader wars in the middle east. every so often he just seems to react or vent or let loose, and until you see what happens over the next days and weeks, you can't really know if this was just weeks, you can't really know if this wasjust him venting or weeks, you can't really know if this was just him venting or if it was a sustainable change in policy. so i'm sorry that i'm talking around your question, but i really don't know how to evaluate the likelihood of a us withdrawal from syria today. he is right to identify that frustration among the voters, isn't he? he and they and many voters want out of foreign wars. do you think he is rolling back the cost of this

move, certainly to the kurds, and to all kinds of alliances, and in the region generally, it is huge, isn't it? no doubt, you are exactly right. and the risks here for president trump of changing policy are far greater than the benefits of staying the course, because with just 1000 us troops and some international help, obviously, from good allies in europe, we managed to sort of stabilised northeast syria. and that's about the only thing that's gone 0k in this whole 8.5 year saga, in that conflict. and you are right to say and i think i was right to say that a lot of voters in the united states are frustrated by these wars, but no—one really talks about them because they are small, they are far away, they don't involve that many casualties. and so if you focus in on it too intently, you can decide it's a big political albatross, but if you take a step back, voters are going to care next year about the economy, about relations with china and russia. this is not going to be what determines the outcome of any election, so i just

determines the outcome of any election, so ijust don't see why it has to become an issue. but obviously today, at least, president trump disagrees. thank you very much for your insights. my pleasure, thank you. let's get some of the day's other news: china's state broadcaster and the biggest streaming platform, tencent, are no longer going to carry games played by the american basketball team the houston rockets, because their general manager tweeted his support for hong kong's pro—democracy movement. daryl morey has since deleted his tweet and apologised to china. hong kong's government is considering restricting access to the internet to try to contain the protests. an emergency law banning the wearing of face masks only stoked tensions at the weekend and led to more clashes with police. dozens of people have been arrested for flouting the new law. the swedish king has removed five of his grandchildren from the royal house. they will no longer have the title of royal highness and will not perform official royal duties, but will remain members of the family and retain their titles. it reflects a wider view that there is no need to pay so many

members of the family for official duties. thousands of climate change activists have been on the streets in cities around the world starting two weeks of global protest. the campaign, co—ordinated by extinction rebellion, is pushing for much more urgent government action to stop rising carbon emissions. in london, there were more than 250 arrests as protesters blocked bridges and roads in the centre of the capital. our chief environment correspondent justin rowlatt has the latest. there wasn't much the police could do as vehicles blocked key junctions and protesters swiftly chained themselves underneath. careful, mate. we're trying to shut central london to draw attention to the climate and ecological violence. go, go, go, go, go, go go! but officers drew the line when activists tried to set up a kitchen — yep, sink and all — in the middle of trafalgar square. this was a numbers game.

there were hundreds of police. there are no official numbers yet, but thousands of protesters. campsites and kitchens quickly sprang up in the heart of government. there was even an impromptu wedding on westminster bridge. cheering and applause it brought parts of central london to a standstill. everyone's going to lose money. i might as well go home now. my day's finished. i ain't going to earn nothing, am i? it certainly was disruptive. it took hours for police to unglue protesters from this scaffolding tower. and how would you cut this guy free from his hearse? not everyone agreed with the tactics. i think you're hysterical extremists, and you are alienating public opinion, and they ain't going to turn off their lights until you ask them to individually. celebrity supporters defended the action. this is a movement for everybody. this is not about party politics,

it's not about brexit, it's much, much bigger than all of that. and it wasn'tjust london. extinction rebellion protests included a mass lie—in in mumbai, roadblocks in berlin, actions in new zealand, and in dublin, too. the crowds are thinning out now, though some activists do plan to sleep over, despite the rain. but it's unlikely to be comfortable, especially when you are chained to a friend. what are your plans for tonight? to stay here, keep the strand blocked — yeah, keep the blockage up. aren't you worried the police are going to come and arrest you in the middle of night? no, a cell might be a bit drier than this. # we're getting stronger by the hour... and remember that guy in the hearse? he is still there, though now his passenger is wearing the bike lock. one of the co—founders of extinction rebellion says these dramatic gestures are needed. people have got to get their heads around how serious this crisis is. it's not going away. asjustin was mentioning in his report, there were protests throughout the globe. our correspondent nada

tawfik is in new york. it's been a scene of really orderly chaos, i would say. the extinction rebellion protesters hitting a lot of the iconic spots of new york city. first, at the charging bull, down by wall street, they sprayed it with fake blood and staged a die—in. around 30 people were arrested between there and the stock exchange, where they continued the protests, before they went up to lower manhattan and blocked traffic on broadway avenue. again, 50 people there arrested. but police have really been trying to contain the protesters, mark out the route and surround them, so it won't get too out of control. and now here, they are beginning what is supposed to be a week of activities, trying to get people signed up and aware of their cause. a stolen truck has ploughed into several cars in the centre of the german city of limburg. at least 17 people have been injured and one is in a critical condition. the driver of the vehicle, who was also injured, has been arrested.

police said it was too soon to speculate about a motive and that the investigation is ongoing. germany has been on alert following several jihadist attacks in recent years claimed by the islamic state group. the university of lagos has confirmed it has indefinitely suspended one of its lecturers in the light of a bbc investigation into allegations of sexual harassment of students. boniface igbeneghu was one of several academic staff at two universities in west africa caught on camera offering admission or higher grades to women in exchange for sex. officials at the university of lagos said they have a zero—tolerance policy on sexual harassment. mr igbeneghu has also been suspended from the church where he preached. stay with us on bbc news. still to come: new zealand marks 250 years since british explorer captain cook landed, and the first encounter between maori and europeans. this was a celebration by people

who were relishing their freedom. they believe everything's going to be different from now on. they think their country will be respected in the world once more as it used to be before slobodan milosevic took power. the dalai lama, the exiled spiritual leader of tibet, has won this year's nobel peace prize. as the parade was reaching its climax, two grenades exploded and a group of soldiers jumped from a military truck taking part in the parade, and ran towards the president, firing kalashnikov automatic rifles. after 437 years, the skeleton ribs of henry viii's tragic warship emerged. but, even as divers worked to buoy her up, the mary rose went through another heart—stopping drama. i want to be the people's governor. i want to represent everybody. i believe in the people of california.

this is bbc world news. the latest headlines: president trump is accused of abandoning america's kurdish allies as he withdraws us troops from northern syria. hundreds of arrests as activists worldwide begin a 2—week campaign of disruption, demanding action on climate change. the british prime minister has urged the trump administration to reconsider the diplomatic immunity of an american diplomat‘s wife who's left the uk even though she is a suspect in a fatal road crash. harry dunn died when his motorcycle was in a collision with a car near an raf base. anne sacoolas left the uk despite telling police she had no plans to do so. duncan kennedy has the details. harry dunn was just 19 when he was knocked off his motorbike last august. he died of multiple injuries. it happened not far

from this american air base in northamptonshire when he collided with a car driven by the wife of a diplomat who worked at the base. that driver was anne sacoolas, pictured here on her wedding day in 2003. but within two weeks of crash, she and her family returned to the united states. this is the neighbourhood near washington, dc where they own a home. it was her decision to leave britain despite being a suspect in a fatal car crash that today led to the prime minister to intervene. i do not think that it can be right to use the process of diplomatic immunity for this type of purpose and i hope that anne sacoolas will come back and will engage properly with the processes of law as they're carried out in this country. the intervention of the prime minister comes six weeks after harry died here on this roadside

in northamptonshire. the air force base where anne sacoolas drove out of is just 200 yards down the road. harry's family say they welcome the move by borisjohnson and say they hope it'll bring real pressure on the american government. harry's parents said today that whilst they are not seeking a long jail sentence for anne sacoolas, they are finding it hard to forgive her. it was an accident, we know this, she didn't mean to kill our son, it was an accident, i can forgive herfor that. but forgive her for leaving? we'd have tried to get her a suspended sentence, so she could've carried on being a mum, so that she wasn't taken away from her own children. but forgiveness for leaving — i'm nowhere near. northamptonshire police today said the absence of anne sacoolas is frustrating their investigation. it's difficult when the suspects have left the uk and obviously causes delays

in the investigation, but we're making really hard to make sure we gather all of the available evidence that remains for us. the foreign secretary has today spoken with the american secretary of state. what started as a tragedy on a quiet english country road has become an international cause of division and heartache. duncan kennedy, bbc news. now, take a look at this — this image was captured by the subaru telescope in hawaii. note the white dot highlighted in orange. an hour later, the telescope took this next image, showing the orange dot move with every other celestial object staying in place. these images confirmed for a research team from the us the discovery of a new moon orbiting saturn. and it wasn't alone. the team have discovered 20 new moons orbiting saturn. and that's important, because it has now overtakenjupiter as the planet in our solar system with the most natural satellites. joining us now from washington

is dr scott sheppard, leader of the research team from the carnegie institute, which made the discoveries. very good to talk to you. congratulations. in terms of a nonspecialist would understand, can you explain this. it is not everyday you explain this. it is not everyday you discover one moon let alone 20. we took images with one of the most powerful survey telescopes in existence. it is very large telescope with a very large field of view and we covered the whole area around saturn to find these new moons. so you when using new techniques to analyse old data, essentially? yes, we took these images a few years ago but computer power has advanced in the last few yea rs power has advanced in the last few years and our computer has also advanced. we put these new ideas to some old data and were able to pull out 20 new moons of saturn. they are very faint, fairly small. three to five kilometres in size. but they

we re five kilometres in size. but they were all there in the data and we we re were all there in the data and we were able to pull them out. they are just points of light at the moment. you don't know much about them. why are they particularly of interest? these outer moons of saturn, we believe they are the remnants of a planet formation. most of the objects in the giant planet region wherejupiter objects in the giant planet region where jupiter and saturn are objects in the giant planet region wherejupiter and saturn are have been either incorporated into the planets or rejected out of the area, and so we think these moons were ca ptu red and so we think these moons were captured by saturn just after the planet formation process and we think these other blocks of the planets, the last remnants of the small objects. does that mean if you can analyse them more closely, you will know more about how the planet itself was formed? yes, we want to determine the composition of these objects to see basically what the planets were originally made of, the building blocks. they arejust points of light so we will need the next generation of telescopes to really a nalyse next generation of telescopes to really analyse these objects and determine what they are. we think they are probably comet like

objects, half water ice and half rock, that kind of material. objects, half water ice and half rock, that kind of materiallj objects, half water ice and half rock, that kind of material. i have to ask you a question on behalf of schoolchildren beyond the globe. —— schoolchildren beyond the globe. —— schoolchildren around the globe. we wa nt schoolchildren around the globe. we want the whole world to name these new saturn moons. they could be named after mythology and you just go to twitter and you type in the # #namesaturnsmoons. thank you so much. now, new zealand is marking 250 years since the british explorer captain james cook set foot in the country. a replica of his ship, the endeavour, has arrived at the same spot in gisborne to a mixture of celebrations and protests. our correspondent phil mercer is there. the arrival of the replica of james cook's ship the endeavour is once

again reignited debate here in new zealand about the legacy of captain james cook. many maori people, his arrival was the start of a brutal colonisation. they say the effects of invasion, as they call it, i still felt today. maori people make up still felt today. maori people make up about 15% of the population, but they suffer disproportionately high rates of ill—health, imprisonment and suicide. too many other new zealanders today, it is a time of great celebration. they are commemorating an important chapter in their european history. we have seen hundreds of people gather around the bay today to watch this ship sale in two lisbon harbour. 250 yea rs ship sale in two lisbon harbour. 250 years ago was the first time that europeans had contact with maori people on the ground here in new zealand —— gisborne. a very significant day, a very divisive issue when we consider the legacy of james cook. was he a barbarian? was

he an invader or was he a father of the nation? discuss. phil mercer there in gisborne, new zealand. the british scientist sir peter ratcliffe has been named as one of three recipients of this year's nobel prize for medicine. celebrating today in his laboratory at oxford university, sir peter will share his prize with two american scientists for research into how cells sense and adapt to oxygen levels leading to potential breakthroughs in treating disease. just for a moment, the serious work of science was put on pause at sir peter ratcliffe's laboratory at the university of oxford. in true nobel fashion, so peter had no advanced warning of the prize. fashion, so peter had no advanced warning of the prizelj fashion, so peter had no advanced warning of the prize. i found out this morning as my secretary catherine came through the door into my laboratory with an anxious look on herface my laboratory with an anxious look on her face and suggested my laboratory with an anxious look on herface and suggested i my laboratory with an anxious look on her face and suggested i talk to someone on her face and suggested i talk to someone from stockholm. what was your reaction? well, delighted, honoured. a little bit surprised this morning. bob usually this is a

great tribute to lots of people in my life, the people whose help me set it up, the people who have been there for years and who are there now. in 2019, nobel prize in physiology jointly to william... sir peter share the award with american scientist william calen and greg semenza for their discoveries on how human cells sense and adapt to the availability of oxygen. for elite athletes like dean asher smith powering her way to gold the 200 metre world championships, muscle cells are perfectly calibrated to get maximum explosive power. for mountaineers at higher altitudes, oxygen levels can be dangerously low, kin to what patients experience in intensive care. discovering how the human body adapts to extreme situations has many medical applications. most human diseases

are complicated by low oxygen. we call it hypoxia. that includes heart disease, anaemia. the primary target now, cancer in a slightly different way. we're right on the threshold of hearing the outcome of trials in the us, in europe and japan. sir peter's share of the prize money is nearly £250 million. he says he has no idea how he will spend it and seemed anxious to get back to his lab. before we go, it's not every day you see something like this swimming in london's river thames. a humpback whale has been spotted for the first time in around ten years. it's over 80 foot, or nearly 30 metres long, and doesn't seem to be in any distress. scientists monitoring the animal say its behaviour is "perfectly normal". there is more on all the news any

time on the bbc news website. and you can get in touch with me and most of the team on twitter. i'm @bbcmikeembley. thank you for watching. hello there. this week is looking typically autumnal, quite unsettled, windy at times and there will be plenty of showers in the forecast. also, some sunshine, it won't be a washout all the time, but when you catch one of these showers, they will often be quite heavy. maybe with a rumble of thunder and some hail mixed in too. all down to low pressure, which will be just to the north—west or to the north of the uk over the next few days and indeed for much of the week. so our air will be coming in off the atlantic with these weather fronts bringing in bands of showers. one thing you will notice, though, it's not going to feel particularly cold, we will have our air source coming in off the atlantic from a west or south—westerly direction most of the time. so that means around average

temperatures through the day. and at night, it should keep the frost and fog at bay. so for tuesday, it's going to be a bright, sunny start across many central and eastern areas, plenty of showers across to the west but will tend to work their way through, and they'll be blown in on a strong wind. so they'll move through quite quickly despite them being quite heavy in places. like i said, with thunder and hail. and the winds will be gusty, very squally, 40—50mph in places, so this won't be with you for long. temperature—wise, highs of 16 or 17 degrees, generally the low to mid teens further north, particularly where you hold on to frequent showers. as we head to tuesday night, it looks like those hours, blustery, continue across northern and western areas, central and eastern areas may tend to turn drier, in fact, with clear skies. most temperatures no lower than around 7—10 degrees. for wednesday then, low pressure still with us just to the north of the uk, tightly packed isoba rs, so another windy day, and these weather fronts producing bands of showers. there will be one heading into parts of england and wales,

i think, through wednesday morning. so we will see an enhancement of showers across western areas through the morning into the afternoon. there could be a cluster of some heavy, maybe thundery ones pushing across south wales and southern england. again, further north, closer to that area of low pressure, this is where we'll see most of the showers across western scotland. temperatures on wednesday probably a notch down on tuesday's values. on into thursday, low pressure again to the north of the uk, it's going to be another pretty windy day. bands of showers moving from west to east, most of them against across the north and the west of the country. eastern areas may tend to stay dry with some showers arriving through the afternoon later on. temperatures again 13—16, maybe 17 degrees in the south—east. and it remains unsettled from thursday onwards, you can see sunshine and showers, those temperatures around the seasonal average, and it remains windy as well.

this is bbc news. the headlines: president trump has been angrily defending his decision to pull american troops out of northern syria, a move that opens the way for an attack by turkey on kurdish fighters. mr trump has threatened to decimate the turkish economy if they go what he called off limits. thousands of climate change activists have begun two weeks of global protest. the campaign, co—ordinated by extinction rebellion, is pushing for more urgent government action to stop rising carbon emissions. in london, there were more than 250 arrests as protesters blocked bridges and roads in the capital. a replica of the endeavour has been marking the 250th anniversary of captain james cook landing in new zealand. he had set sail from the yorkshire port of whitby. it is not without controversy, as some maori communities see cook's arrival as the start of the marginalisation of the maori people.