Reports are now coming of loud explosions in Ukraine's southern port of Odesa.

Smoke was seen in the strategic city on the Black Sea coast on Sunday morning, a Reuters witness said.

Washington Post correspondent Isabelle Khurshudyan, who is in Odesa, tweeted: "Loud explosions in downtown Odessa right now. My hotel room windows just shook. Not clear what that was."

Serhiy Bratchuk, a spokesman for Odesa's regional military administration, urged city residents to stay in shelters.

"We will overcome. Hell to enemies!" he wrote in a Facebook post.

Katya Adler
Europe Editor

Yes and no.

Nato is re-invigorated, the EU has been elevated into a credible geopolitical player, and its richest and most powerful member, Germany, suddenly said goodbye to World War Two sensitivities and announced huge investments in its military.

But for all Brussels' talk of the EU building "strategic sovereignty", it looks to Washington when faced with Russian threats.

EU defence plans, designed to complement - or to partly replace - Nato, are nothing new. And so far, they've never worked.

All the countries agree that it makes sense to pool resources and know-how. Yet, no nation wants to go first.

But the EU has its raison d'être back. Designed originally as a peace project, its vision fell by the wayside in recent times.

In that regard, this moment really is a new reality.

Some more now on what's left of the Antonov An-225 - known as Mriya (Dream) - the aircraft that was once the largest in the world by several measures.

The Ukrainian cargo plane was being housed in a hangar at Kyiv's Hostomel Airport, which became a fiercely contested site of intense fighting after the invasion was launched.

The Ukrainian state defence company put the cost of rebuilding the craft at $3bn., external

Russian forces have now withdrawn from the airport. The BBC visited on Saturday and found the wreckage of the plane in a hangar.

Image source, BBC/Jeremy Bowen

Image source, Babylon"13/

Image source, Perth Airport

Image source, Supplied

"Until I saw the video, I still had some hope. I was hoping that he was alive."

Sergiy Iovenko's son Maksim was shot dead by Russian forces on 7 March. His wife, Ksenia, was killed as well. The incident was filmed by a Ukrainian territorial defence group doing aerial reconnaissance, and has since been widely shared.

The couple were killed while trying to flee from the western outskirts of Kyiv.

With them were their six-year-old son and an elderly family friend, who was injured. Both escaped, but are said to be traumatised.

Sergiy describes Maksim as a family man with a kind heart who liked to sing karaoke.

Read the full story here.

With new evidence emerging of civilian killings in the Kyiv area and the continuing fighting elsewhere in Ukraine, is there any hope of a peace agreement?

Ukraine's chief negotiator said on Saturday that the talks had advanced far enough for President Volodymyr Zelensky to potentially speak to his Russian counterpart, Vladimir Putin.

Davyd Arakhamia reported progress at talks between delegations by video link on Friday, saying Russia had accepted Ukrainian proposals on all issues except Crimea, the territory Russia annexed from Ukraine in 2014.

Draft documents were at such a stage, he said, that the two presidents could hold consultations directly, but work was continuing on several issues apart from the document itself.

There was no immediate comment from Russia. Its chief negotiator, Vladimir Medinsky, said after Friday's talks that Russia's positions on Crimea and Donbas had not changed.

Russia insists that Ukraine recognise Crimea as Russian, and recognise the independence of the Donbas, where Russian-backed rebels control a large chunk of territory.

Lithuania’s energy ministry on Saturday said the country would no longer import natural gas from Russia - saying it was breaking "energy ties with the aggressor".

"If we can do it, the rest of Europe can too," President Gitanas Nauseda tweeted.

Russian leader Vladimir Putin has been demanding that foreign buyers pay for Russian gas in roubles, threatening to cut off supplies.

Ukraine has said that its forces have retaken the entire region around the capital Kyiv, with Russian forces withdrawing from key towns.

Hostomel airport near Kyiv, which has seen fighting since the first day of the conflict, is now back in Ukrainian hands.

As Russian troops retreat, the evidence of civilian killings - a war crime - is growing.

Reporters in the town of Bucha, which is just outside Kyiv, have found at least 20 bodies left in the streets.

The BBC's Jeremy Bowen reports from Bucha and Hostomel. His report contains some distressing images.

Image source, Ukrainian President's Office

Russia wants to seize Ukraine's eastern and southern regions, Ukrainian President Volodymyr Zelensky has warned.

In a video address late on Saturday, he said: "What is the goal of the Russian troops? They want to capture both Donbas [in the east] and the south of Ukraine.

"What is our goal? Protect ourselves, our freedom, our land and our people."

Zelensky also praised Ukrainian forces defending the besieged southern port of Mariupol, which has been virtually wiped out by weeks of heavy Russian bombardment.

The Ukrainian resistance in Mariupol and other Ukrainian cities allowed Kyiv to "gain priceless time", helping to weaken Russia's military capabilities, the president said.

Earlier this week, Russia announced that it would "drastically reduce" combat operations around the capital Kyiv and the northern city of Chernihiv, and instead focus on Ukraine's eastern regions.

Russia has stepped up air activity towards south-eastern Ukraine in the past week, the UK Ministry of Defence says in an intelligence update.

It echoes a warning a few hours ago from President Zelensky, who said Russia wants to seize the south and east of the country.

However, the Ministry of Defence says Ukrainian forces are mounting a significant challenge to the Russians in the air - hampering their ability to secure the region on the ground.

Kasia Madera and Rebecca Hartman
Lublin, Poland

Five hours after Russia invaded Ukraine, Lublin's Committee for Ukrainian Refugees was up and running.

A mixture of NGOs, volunteers and private business supported by the local council, its nerve centre is at the city's Centre for Culture.

This former monastery was initially used to house refugees who had reached the town, exhausted and in need of rest. Camp beds are still set up for those who continue to pass by, but the need for this building has changed.

It is now the location of the call centre where Ukrainian refugees can get advice and support. It is also where local people who offer accommodation to refugees are vetted.

According to local officials the city currently hosts around 35,000 Ukrainian refugees. Some 1,300 are in temporary accommodation, but the vast majority of these have been found a place to live, many with local residents.

In total, according to the UN, over four million people have left Ukraine since the war started. Around 2.4 million have crossed into Poland according to the Polish border force.

Video footage verified by the BBC appears to show Ukrainian forces using a high-velocity British-supplied Starstreak projectile to shoot down a Russian MI-28 helicopter in the Luhansk region of eastern Ukraine.

UK Defence Secretary Ben Wallace confirmed in March that the UK had supplied Ukraine with the anti-aircraft missiles.

The Ministry of Defence has declined to comment on the footage.

Image source, Getty Images

Pope Francis appeared to criticise Russian President Vladimir Putin over the invasion of Ukraine earlier, saying a "potentate" - a ruler - was stirring up conflict for nationalist interests.

Speaking in Malta, the Pope said: "Once again, some potentate, sadly caught up in anachronistic claims of nationalist interests, is provoking and fomenting conflicts, while ordinary people sense the need to build a future that will either be shared or not be at all."

Asked earlier by a reporter on the papal plane about a possible trip to Kyiv, the Pope said a visit to Ukraine's capital was "on the table".

Ukrainian officials say the country's forces have recaptured the whole region around Kyiv. It follows fierce fighting in several towns and villages around the capital in recent weeks.

Russia has depicted its drawdown of forces near Kyiv as a goodwill gesture in peace negotiations but Western analysts say its offensives had stalled anyway.

Here are some of the key areas you might be hearing about:

Irpin

Authorities say at least 200 civilians have been killed in Irpin, a short drive north-west of Kyiv, since Russia invaded Ukraine in late February.

Most of the 70,000 people who used to live in this middle class commuter city fled over the past month - darting out of basements and running the gauntlet of relentless Russian shelling.

Our correspondent Orla Guerin visited earlier this week - read her report here.

Image source, Reuters

Bucha

Ukrainian troops have only moved into Bucha in the past day or two - it had been completely inaccessible for nearly a month.

On Saturday, the AFP news agency saw at least 20 bodies on a single street. The town's mayor meanwhile said 280 people had been buried in a mass grave in Bucha and that the town was littered with corpses.

You can read our full report here - but we'd like to warn you that the story contains some distressing content.

Hostomel

Hostomel, also near Kyiv, was the setting of heavy fighting from the very beginning of the war to take control of an airfield - home to the world's largest aircraft, the Antonov An-225 Mriya.

The carcass of the aircraft remains in a hangar there, which our correspondent Jeremy Bowen visited earlier today after Russian forces abandoned the area.

Image source, Reuters

We wrote earlier about the discovery of 20 bodies on a street in the town of Bucha, near Kyiv, which AFP news agency journalists visited after Ukrainian forces won back control.

More details of the carnage in the town, which was recaptured by Ukrainian forces this week, are being reported.

Mayor Anatoly Fedoruk told AFP by phone that all 20 victims had been shot dead. Other bodies, he said, still lay inside the wrecks of cars destroyed by shelling.

The town, he said, had buried 280 people in mass graves as a result of the Russian invasion. Photos show damaged buildings and crushed vehicles.

We have a story with more details here - but some readers may find the content distressing.

Estonian officials say Ukrainian refugees arriving from Russia include some moved out of besieged Mariupol into Russian territory.

Ukraine has accused Russian forces of "deporting" thousands of civilians from Mariupol, a port city devastated by Russian shelling. Russia denies forcing people to leave, but says it is looking after thousands of people from there.

Indrek Puvi, the police chief of Narva, on Estonia's border with Russia, said some 200 Ukrainian war refugees had entered EU member Estonia daily in the past week. Besides people from Mariupol, there were refugees from Kherson, Kharkiv and other cities.

He told public broadcaster ERR that some had entered Russia voluntarily because they had been unable to flee to western Ukraine. "However, there have also been people who were forcibly directed to Russia and allowed to leave on their own after arriving there," he said.

The BBC has been unable to verify the numbers evacuated to Russia.

Russia is battling to take Mariupol in order to link up Crimea with Donbas. Its forces seized both territories in 2014.

Image source, Reuters

If you're just joining us - or want a recap on the latest developments - here's a quick roundup:

Ukrainian progress

• Ukraine claims Russian forces have made a "rapid retreat" from around Kyiv, with the deputy defence minister saying the whole region around the capital has been retaken
• Russian forces have been pulling back from key towns including Irpin and Bucha

• They have also abandoned Hostomel airport near the capital, leaving behind the wreckage of the world's largest aircraft

New evidence of atrocities

• As Russian forces retreat, journalists in Ukraine say they've seen at least 20 bodies - dressed in civilian clothes - on a street in a town near Kyiv
• The reporters travelled to Bucha with Ukrainian troops, after Russian forces retreated
• One commander said all men aged between 18 and 60 had been rounded up and executed by Moscow's soldiers
• Meanwhile, the mayor of Bucha told AFP news agency a mass grave in the town contained 280 bodies
• Ukrainian authorities said the body of a well-known photographer, Maks Levin, had been found near a village in the region around Kyiv

Humanitarian corridors

• Hundreds of residents of Mariupol have managed to escape the besieged city in private cars and have arrived at reception centres hundreds of kilometres to the north
• But a third attempt in a row by the Red Cross to bring a fleet of dozens of buses to the southern Ukrainian port has once again been frustrated
• This time they are spending the night en-route and will resume their journey in the morning

Ukraine's deputy defence minister says the country's forces have retaken the whole Kyiv region.

Hanna Malyar said in an update, external on Saturday: "The whole Kyiv region is liberated from the invader."

The BBC has not been able to verify her claim but Ukrainian forces have been retaking territory around the capital city in recent days as Russian forces pull out.

Image source, AFP

The northern city of Chernihiv had its first quiet night on Friday since the Russian invasion on 24 February, the city's deputy mayor tells the BBC.

Oleksandr Lomako said that "thanks to the enormous efforts of our army, Russian troops fled from most of the villages around Chernihiv". He was interviewed by Newshour on the BBC World Service.

There is heavy damage to Chernihiv's infrastructure, after weeks of Russian shelling and air raids.

The local governor, Vyacheslav Chaus, confirmed on Telegram that "the night in Chernihiv and Chernihiv region was calm". He too said the Russians were retreating.

Western and Ukrainian analysts believe the Russian pull-back in parts of the north is a regrouping exercise, ahead of a new Russian offensive in the east. Russia has spoken of re-focusing its war on the Donbas region.

Video footage verified by the BBC appears to show Ukrainian forces using a high-velocity British-supplied Starstreak projectile to shoot down a Russian MI-28 helicopter in the Luhansk region of eastern Ukraine.

UK Defence Secretary Ben Wallace confirmed in March that the UK had supplied Ukraine with the anti-aircraft missiles.

The Ministry of Defence has declined to comment on the footage.

Journalists from the AFP news agency with the first Ukrainian troops to enter the town of Bucha after Russian troops retreated have seen at least 20 bodies strewn along a single road.

Bucha, just outside Kyiv, has witnessed some of the heaviest fighting in recent weeks.

In footage posted online, bodies were seen along a road in the town as if they had been dumped from the back of a truck. All appeared to be wearing civilian clothes.

Some have their hands tied, with bullet wounds to the head.

Footage shows residential buildings with gaping holes from shellfire, and crushed cars littering the streets.

Bucha - along with nearby Irpin - has seen weeks of fierce fighting, as the Russians tried to encircle the capital.