this is bbc news, the headlines. the russian government says one of it's leading war bloggers has been killed in an explosion at a cafe in st petersburg, russia's second largest city. sixteen other people were injured. vladlen tatarsky was a vocal supporter of russia's war in ukraine and was holding a meeting at the venue. authorities in the united states have been assessing the damage caused by storms and tornadoes. at least 26 people are known to have died and dozens are missing. the bbc has been told there are �*positive updates�* in the case of british men, who were arrested by the taliban in afghanistan earlier this year. in finland's general election, the centre—right leader, petteri orpo, has claimed victory after the prime minister and leader of the social democrats, sanna marin, conceded defeat after a nail—biting race. ms marin governed with a coalition

of five parties, all led by women. time for some sport here on bbc news. hello i'm hugh ferris. afterjust seven months in charge, graham potter has been sacked by chelsea. losing again yesterday saw them drop to 11th in the premier league and they weren't the only top flight team to part company with their manager today. here's nesta mcgregor. ato a to know the feed to aston villa at stamford bridge a result that salt chelsea drop it to the bottom half of the premier league fans far from happy and 11th defeat in 31 games. although graham potter was optimistic. iii although graham potter was optimistic— although graham potter was otimistic. ,, ., , ,, optimistic. if you look at the steps a art from optimistic. if you look at the steps apart from the _ optimistic. if you look at the steps

apart from the main _ optimistic. if you look at the steps apart from the main one _ optimistic. if you look at the steps apart from the main one there - optimistic. if you look at the steps apart from the main one there a l optimistic. if you look at the steps| apart from the main one there a lot of positives there but it doesn't feel too positive. just of positives there but it doesn't feel too positive.— feel too positive. just over 24 hours later— feel too positive. just over 24 hours later a _ feel too positive. just over 24 hours later a statement - feel too positive. just over 24 hours later a statement from | feel too positive. just over 24 i hours later a statement from the club thanking him for his contributions, but announcing his departure after less than seven months in thejob. after what departure after less than seven months in the job. after what could be considered a successful three seasons at brighton, one of your biggest clubs proved to be too much. joining in a five—year deer which came with heavy financial support he spent around 300 million around january�*s transfer window. but despite reaching the quarterfinals of the champions league chelsea's domestic form fell short of the european exports.— domestic form fell short of the european exports. domestic form fell short of the euro--eanexorts. ., ., , ., european exports. company wants to cive european exports. company wants to give graham _ european exports. company wants to give graham potter _ european exports. company wants to give graham potter every _ european exports. company wants to give graham potter every possible i give graham potter every possible chance _ give graham potter every possible chance i_ give graham potter every possible chance i think it is for wins and 16 now and — chance i think it is for wins and 16 now and under previous he would've gone a _ now and under previous he would've gone a long — now and under previous he would've gone a long time ago.— gone a long time ago. there have been numerous _ gone a long time ago. there have been numerous changes - gone a long time ago. there have been numerous changes in - gone a long time ago. there have . been numerous changes in managers the season with leicester city having parted company with micro to

a few hours earlier on not such a super sunday. fortwo a few hours earlier on not such a super sunday. for two of britain's most respected coaches brendan rodgers ——. in the premier league today newcastle are back up to third.. ahead of the team they beat... manchester united. joe willock scored the opener in the second half with a header as newcastle got a little revenge for their defeat to united in the efl cup final, substitute callum wilson made the game safe with less than 5 minutes to go. the victory puts eddie howe's side firmly in the hunt for a champions league place. important win, i think it was most importantly, a really good performance from the players, i thought from start to finish, really high energy, real quality, a lot of chances created so delighted. we kept knocking on the door, tribute to our fitness level, we got stronger throughout the game even though we were giving so much and our substitutes made an impact, and that was a huge part. west ham have picked up a crucial victory in the meeting of the premier league's bottom two teams. nayef aguerd scored in the 1—0 win

over southampton that takes them out of the relegation zone, while their opponents stay at the foot of the table. celtic have restored their nine point lead at the top of the scottish premiership with a 2—0 win at ross county. the goals came just before half time and just before the end. alexandro bernabei sealing the victory in the 95th minute. the thrilling women's super league title race has ta ken another twist — chelsea are second, a point behind leaders manchester united after winning 3—0 at aston villa. while arsenal went above another contender manchester city by beating them 2—1. katie mccabe with the winner. arsenal are three points off the top with a game in hand. max verstappen won the australian grand prix, but the world champion controlling another formula one race was the only unsurprising thing that happened in melbourne. behind him lewis hamilton finished second amid a good deal of disarray. ben croucher reports.

on sunday down under, f1 turned topsy—turvy. its lights out and away we go. do when you need a healthy mix of luck and skill, verstappen had an early lead but behind the luck for the clare runner up i turned three. running out a few laps later, categorised by chaos and crashes, although the subsequent red flag dropped russell down to seven. on the restart, max verstappen was running red hot to hit the front and scamper off into the distance, the dutchman maybe not as warm as russell whose luck was extinguished in flames. more carnage, three separate incidents, both taking each other out and nobody could quite fathom it. the leaders avoided at all and sometimes, better lucky. better in verstappen�*s case,

but you're still very good. england have recorded another comfortable victory in the women's six nations to go back to the top of the table. they scored 12 tries in a 68 points to 5 win over italy, four of them coming from abby dow. new captain marlie packer also scored twice. and that's all the sport for now. this is bbc news. we'll have all of the headlines and main news stories for you at the top of the hours straight after this programme. it seems extraordinary. witness gasps whoa! rumbling boom did you hear that? unidentified flying objects, talk about aliens, high—tech spying and high—altitude balloons. the united states sent the message to china that "if you invade our sovereignty,

we'll shoot it down." us militaryjets firing expensive missiles at objects which end up being no real threat. it might all sound like something out of a sci—fi novel, but there are some serious issues here. the big question is, how much of a security threat are balloons? so, everyone's been talking about balloons lately. there are lots of different theories and speculation flying around. i'm going to try and break all this down to what we actually know and talk to a couple of experts about why we've seen this reaction from the americans and a row with china. but let's recap first — how did this crisis start? for those of you who think this mightjust be the moon, it is not the moon. the moon is off to my right, i can see it.

people of montana started posting about something strange in the sky. airspace had to be closed, and soon us officials had to explain what this really was. we know that it's a surveillance balloon and i'm not going to be able to be more specific than that. china responded by saying it was just a weather balloon that had been blown off course. the us military said they couldn't shoot it down for fear of causing debris or damage below, so it was only when it drifted across america and out over the atlantic that they eventually shot it down. the spotting of the first balloon led north american air defence — norad — to adjust their radar settings. domestic political pressure may have played a part. this is the atrocity that's happening here to america. and if we don't speak stronger, china will continue to do this. scramble some more f—22 raptors, throw some lead in that sucker. trump wanted to nuke a hurricane. you guys won't even throw

a dart at a balloon? there was outcry in america as to why a massive spy balloon had not been spotted and shot down earlier. but that meant in the next few days, they were now seeing many more of what were described not as balloons, but objects. if anything enters into our airspace, whether we know what it is or not, we will monitor it and we'll take appropriate action. one was seen over alaska and shot down near a place called deadhorse on february 10th. the next day, another object was shot down over the yukon in canada. and then on february 12th, a strange octagonal object was shot down by fighters over lake huron. these were lower and smaller than the first balloon, but they could have got in the way of civilian airliners. there seemed to be things in the sky everywhere. at the same time, china began accusing the us of flying its own high—altitude balloons into chinese airspace without beijing's permission — on more than ten occasions in the last year, they said. translation: it is also common

for us balloons to illegally enter| the airspace of other countries. since last year alone, us high—altitude balloons have illegally flown over china's airspace more than ten times without any approval from relevant chinese authorities. the first thing for the us to do is introspect itself and change its course, instead of slandering and inciting confrontation. amid growing speculation about what's going on and after one military official refused to rule anything out, on february 13th, the us decided it needed to clarify one thing — these objects were not aliens. i know there have been questions and concerns about this, but there is no, again, no indication of aliens or extraterrestrial activity with these recent takedowns. maybe this is the point to address the ufo issue. they exist — they're actually called unidentified aerial phenomena now, and there are hundreds of reports from us pilots about them which get catalogued.

they get investigated, not so much because they might be extraterrestrials or aliens, but because the us fears they might be some new technology from another country. and many of those reports may, in fact, have been balloons or similar objects. it's now emerged that the other three unidentified objects shot down between february 10—12 were all, to use the jargon, benign. in other words, perhaps weather balloons or research balloons, but not spy balloons. so, what do we know about the original spy balloon? it was huge — 200 feet tall and helium—filled. there were solar panels to provide power, and sensors and instruments along the bottom. it also had some ability to be manoeuvred and guided, although only limited. it was flying at about 60,000 feet. but it's thought that these kinds of balloons can go up to twice that altitude. and to really understand why they're so useful to china, we need to look at a weather map. wind speeds vary hugely depending on how high up you are.

and at the altitude where this balloon was flying, there is a very stable and predictable wind pattern between china and north america. so, what are the balloons actually being used for? the answer is espionage. they carry sensors to collect signals and data as they fly over locations. us officials are analysing the wreckage they recovered from the sea in order to try and understand what exactly those sensors do and what china was after. you don't need to get into specifics, just, did we know what they're trying to collect, yes or no? yes. — we understand that this is part of a broader suite of operations that china is undertaking... so, we knew what they were looking for. sir, we i think we should talk about this more explicitly in the classified session. but, yes, sir, we understand that this is part of the broader suite of operations that china's undertaking to try and get a better understanding of us. .. i got it _ i mean, there's all sorts of suites of operations we have with what's going on in outer space. but the question is,

did we know what that balloon was trying to gather? do we know what information it was trying to gather from the united states? it didn't fly over us by accident, it was intentional. do we know what the chinese communist government was looking for? senator, we have some very good guesses about that. and we are learning more as we exploit the contents of the balloon and the payload itself. 0k. what might the chinese be trying to find out? lee hudson covers defence and aerospace for politico. lee, what were these balloons doing, particularly these chinese spy balloons? so, it seems, according to the us intel community, that they were gathering not only images, but electronic warfare signals, which means that could be anything from cellphone communication and other types of data, because they were flying over an intercontinental ballistic missile site, over montana, which the us military

typically tries to protect. people at first thought, why balloons? but i guess your point is that there are things balloons offer that satellites and other techniques might not. it can be hard to distinguish where a balloon is coming from. for example, a satellite or a drone, you could say it's coming from x country's military, but with a balloon, it's more benign. and so beijing tried to say that it was being used for meteorological purposes. a bit of deniability about what they're really up to, you mean? what do we know about the chinese balloon programme, then? so, we know that they have been doing this throughout the world, that a lot of these are connected. and this instance with the united states has made the us at least look into the programme more. and so we've gathered information that this has been going on for a while. and do we know if other countries have spy balloon programmes as well? yes, i mean, the

united states has one, so that's a prime example. the united states has balloons off the east coast that are run by customs and border control, that they use for counter—drug interdiction, so they're looking towards south america. does the us think that they were taking pictures, but also collecting some kind of signals as they flew over some of the military sites? yes, absolutely. and i think what we're still trying to figure out is whether us intelligence was able to block those signals from transmitting back to china. that's still a question mark that many have, because if the united states was able to jam those signals, then maybe they weren't as lucky in their attempt. there's a long history going back more than two centuries

of using balloons in surveillance, but they still have value today. the altitude they're flying at means they can do things satellites can't do, loitering longer over targets and also collecting signals, because they're in the atmosphere rather than in space. the chinese programme which the first spy balloon belonged to, us officials say, is run by the people's liberation army, and it's been running for years, with at least three balloons over us airspace during the previous trump administration. but both the us and china may have been keeping quiet about what was going on. that's normal for espionage, but now everyone is looking for these balloons. i want people to know that we'll do whatever it takes to keep the country safe. we have something called the quick reaction alert force, which involves typhoon planes which are kept on 24/7 readiness to police our airspace, which is incredibly important. so what are the challenges in dealing with these balloons?

we're going to bring back our graphic for this part. flying a spy plane lower in the atmosphere would be seen as an aggressive act and much more deliberate than just releasing a balloon into the wind. and meanwhile, a satellite up in space is not seen as such a problem. but balloons are in a kind of grey area in between — and harder to spot. they also pose particular challenges to the military in working out how to take them down. i suspect there's probably a desire to find a way to deflate any potential future ambitions for using these things on a larger scale, excuse the horrible pun. professorjustin bronk is the senior research fellow for air power and technology in the military sciences team at rusi, a think—tank. justin, how does the military deal with balloons? i mean, how do theyjudge whether they're a threat or not? it's a difficult one. so, in terms of dealing with them, first of all, there's the immediate first of all, there's the immediate question of what altitude are they at and what speed

are they drifting at, because the primary means for militaries to detect flying objects is radar, and radar works essentially by bouncing energy off objects and reading the returns. but in order to not get endless false returns if you're looking for something like aircraft or missiles, which would be the normal military things that they're trying to track, they will filter out and drop anything that is moving outside of a given range of speeds. so, this is why military radars, for example, are able to, most of the time, disregard things like clutter from the ground, reflections from trees and reflections from birds, clouds, depending on the frequency of the radar — because those objects are moving relatively slowly or stationary, and so the radar will simply filter them out. the wider you make those kind of velocity gates in terms of what the radar is looking at and what it's disregarding, the more clutter you'll have to deal with, and so the better processing you'll require in order to get usable results for military purposes.

what's happened since the chinese spy balloon incident in the us is that the us appear to have reprogrammed a lot of their surveillance radars for air defence purposes with much, much wider velocity gates. so, they're suddenly seeing a lot of sort of floating objects, of which there are many that are not spy balloons. you know, weather balloons, research balloons, just hobbyists putting cameras up on high—altitude balloons. but they just weren't seeing those before. and so now, having opened up the velocity gate, they're now having to try and classify and potentially intercept a lot more things that they just weren't noticing before. make no mistake, if any object presents a threat to the safety and security of the american people, i will take it down. well, i think we need to focus on the real issue here, which is the impact all of this has had on an already fragile and fraught us—china relationship.

i mean, the united states has long had this sense of inviolability. they haven't had to fight on their own territory since the end of the us civil war. and to discover that they are not as inviolate as they thought they were is a big deal culturally and, if you like, semiotically for the us population, and i think this is what is at stake here. it's quite clear that china has messed up. you know, somebody somewhere should have realised that this programme was ongoing at a time when both china and the united states were keen, bordering on desperate, to put a floor beneath a rapidly deteriorating relationship. nobody seemed to think that the discovery of one of these balloons, airships, dirigibles — call it what you will — might derail this. when the news first came out,

the chinese response was to say that, you know, the united states is making a fuss about nothing. the commentators, newspapers plundered the cliche book to talk about this. and this, i think, is indicative of a fundamental misunderstanding by china of what this means. nigel inkster is the former director of operations and intelligence at mi6. he says international law is clear that countries can act to remove flying objects like balloons from their airspace. it may be that these balloons or something like them have overflown the uk at very high altitude and nobody has noticed them. you know, if the uk wanted to shoot one of these objects down, under international law, it would be entirely within its rights to do so. but i think there will need to be a degree of political consideration applied to this.

after all, the united kingdom is not the united states. we're not a global superpower. but with this increased vigilance, could we see countries shooting down more objects which pose no threat? yeah, it is difficult, especially because a lot of more kind of amateur—type balloons that are floating around may not have filed any flight plans or got any permission. and so there may be very little awareness of exactly what's up there, most of which is entirely harmless. it does pose a challenge, doesn't it, because you've gotjets flying up to try and look and see what they are, which sounds like it's quite difficult for them, and then firing $400,000 missiles to shoot them down, which seems to be the only available option. yeah, even the highest—flying militaryjets, things like the f—22 or the british typhoon, which can operate significantly above 50,000 feet, which is typically where fast jets

tend to stop in terms of going higher, f—22, typhoon can operate up to 60,000 feet or even a little above. it's tricky being up there. there are considerations around pilot life support and pressurisation of the cockpit. typically, aircraft are designed to operate at really extreme altitudes above that, like the u—2 spy plane or the sr71 blackbird, again, spy plane. crews would wear kind of spacesuits, full pressure suits, and most jet fighters aren't equipped for that. also, where there have been previous examples of weather balloons, for example, or surveillance balloons from the us side that have kind of got lost or cables have broken, where fighters have tried to shoot them down at lower altitudes using cheaper gunnery, you've had instances where hundreds or even thousands of cannon rounds have gone straight through the balloon, not gone off, in the sense that the rounds haven't exploded because the skin of the balloon is too insubstantial to trigger the fuse.

and so they've just put tiny holes in them, which doesn't really cause them to leak at any particularly significant rate, and they've just continued. and of course, if it's over a civilian area or, say, the continental united states, a large area, you have to be very careful where you're firing cannon rounds because those will still come down somewhere. it is a difficult thing to solve with military equipment that isn't designed for it. does that mean we're going to have to look at new ways of defending or dealing with balloons, airships, otherthings flying at this altitude? because it sounds like it's possible we might see more in the future. it's not a technology of the past, but one that many countries look like they're developing. it may be that there will be more interest in certainly tracking the use of balloons and potentially developing more specialised capabilities to shoot them down more predictably or with lower cost. the flip side is that, you know, this is not a new technology, and spy balloons are something that have been used significantly by most

powers over the years — particularly during the cold war, they were played around with. there are difficulties with them, which is that it's harder to control exactly where they go, even if they have limited propulsion systems on board. so, while balloons are a niche, they're probably not revolutionary in that sense. it's more a political challenge, and also something that you wouldn't necessarily want to have no answer to in case someone started getting much more creative with what they might try and then do if you had no answer to it, and just let it go unchallenged. so, what are the security risks? in one word — escalation. spying happens all the time, but the first rule of espionage is don't get caught, because when you do, it can turn into a problem. the us learnt this a couple of times. there was a major incident in 1960 where soviet air defences shot down an american spy plane flying at high altitude within its territory during the cold war. and more recently, in 2001, a us surveillance plane

which was flying on the edge of chinese territory was forced to land in china after colliding with a jet watching it closely. that led to a tricky crisis. back then, relations were not that bad. they're much worse today. as we made clear last week, if china threatens our sovereignty, we will act to protect our country — and we did. cheering and applause translation: this behaviour is unimaginable and _ borders on hysteria. it is 100% an abuse of force. it is a clear violation of international practice. if the rhetoric grows and both the us and china feel they need to act tough and shoot things down near their airspace, then tensions will grow and there could be dangerous mistakes. so, are these balloons a real security threat to you and me? they may not be in themselves, but how countries react

or overreact to them could have real consequences. we're already seeing that what's essentially a tool of espionage could significantly increase tensions between the world's two most powerful countries and maybe even spark a crisis. and there's the risk that a lot more innocent balloons could get shot out of the skies by fighterjets. monday morning getting off to a calm and clear start across most parts of the uk that means quite a chilly start but we will see it dry and often sunny weather to take us through the

day. a touch of frost first thing but at this time of year the sun has got some strength to it so temperatures should lift pretty quickly. england and wales and scotland sing large amounts of stress sunshine generally more crowded into northern ireland centre turn quite hazy through the afternoon breeze picking up as well as it will in the north west of scotland. temperatures 9—13 . through monday night, where skies remain clear again through monday night, where skies remain clearagain a through monday night, where skies remain clear again a touch of frost particularly for wales, scotland and bike not quite as cold because the here and there will be more close up bits and pieces of rain as a weak frontal system approaches. bring rain for some as we had through tuesday. ring in the north west of the uk by wednesday. further south and east it will remain largely dry with the spots of sunshine. i frowned.

welcome to newsday, reporting live from singapore, i'm karishma vaswani. the headlines... russia says a pro—kremlin military blogger has been killed in an explosion at a cafe in st petersburg where he was holding a meeting. 16 others have been injured. vladlen tatarsky wrote blogs on the telegram platform from the frontline supporting the russian invasion of ukraine. finland's centre—right leader, petteri orpo, has claimed victory in the general election after the prime minister and social democrat leader, sanna marin, conceded defeat. at least 29 people are now known to have died after severe storms batter the north—east of the united states. parisians vote by a huge margin to end on—street rentals of e—scooters.