If you're just joining us, here's a round-up of the latest developments in Ukraine:

• Ukraine's Deputy Prime Minister Iryna Vereshchuk tells the BBC that the evacuation of around 100,000 people stuck in the shattered city of Mariupol will only work with the UN's help
• The Pentagon announced that the US will host Ukraine-focused defence talks in Germany next week with around 20 countries are expected to join
• UN Secretary General António Guterres will meet Russian President Vladimir Putin in Moscow on Tuesday to discuss what can be done to bring peace to Ukraine

• Meanwhile, Russia says it has captured an arms depot in the Kharkiv region. The depot contains thousands of tonnes of Ukrainian ammunition and is now said to be in Russia's hands
• The UK's Ministry of Defence has said that Challenger 2 main battle tanks will be sent to Poland, and these would then be intended to "backfill" for the T72 tanks that Poland is sending directly to Ukraine. But there are no plans to send British tanks or crews to Ukraine
• German Chancellor Olaf Scholz said Nato must avoid a direct military confrontation with Russia, as it could lead to a third world war
• A new mass grave has been reported near Mariupol, according to the city's mayor's adviser Petro Andryushchenko
• A EU official said the upcoming weeks will be decisive for the war and it is likely that there'll be "a very significant increase in the intensity of Russian military attacks in the east"

• Mariupol's mayor Vadym Boychenko told the BBC that a frightening amount of people have been killed by Russian troops in Mariupol. Satellite images have emerged from Maxar technologies, a US satellite company, which shows mass graves in the besieged city of Mariupol

• The UN's High Commissioner for Refugees said 5,133,747 Ukrainians have fled the country since the beginning of the war on 24 February, with six out of 10 refugees going to Poland

Image source, Reuters

One sailor died and 27 more are missing after the Russian warship Moskva sank last week, according to RIA news agency citing Russia's defence ministry.

It adds 396 other crew members were rescued from the Moskva, which was the flagship of Russia's Black Sea fleet.

Russia says a fire onboard caused ammunitions to explode and the vessel sank as it was being towed in a storm. Ukraine says it hit it with missiles.

Read more here.

The US military expects that more than 20 countries will attend talks it's hosting in Germany next week, which will include discussions on Ukraine's long-term defence needs.

Around 40 countries were invited to attend the talks on Tuesday 26 April - the same day as UN Secretary General António Guterres is to meet Russian President Vladimir Putin in Moscow.

Pentagon spokesman John Kirby says they are not being organised under the Nato alliance umbrella - and will be open to non-Nato countries.

He adds that the US is "not going into this with a pre-cooked set of endings".

Russia is likely to continue to be "frustrated" by its inability to overcome Ukrainian defences, the UK's Ministry of Defence (MoD) has suggested.

In its latest intelligence update,, external the MoD highlights comments from Russian Defence Secretary Sergei Shoigu, saying he stated an intent to introduce “new methods of warfare”.

This "is a tacit admission that Russian progress is not going as intended", the UK says.

But the MoD adds "it will take some time to translate this into adapted tactics, techniques and procedures", adding "in the interim there is likely to be a continued reliance on bombardment as a means of trying to suppress Ukrainian opposition to Russian forces".

Why the battle for the Donbas will make or break everyone’s planspublished at 20:00 British Summer Time 22 April 2022

20:00 BST 22 April 2022

Paul Adams
BBC Diplomatic correspondent

For the West, arming Ukraine is a race against time. As a full-scale Russian offensive in the Donbas begins to unfold, so the pace and scale of Western assistance increases.

Britain’s arrangement with Poland to get tanks to Ukraine mirrors a similar deal between Germany and Slovenia. And the United States has just offered another $800m worth of equipment – the third package of this size in just over a month.

It includes artillery pieces that are much more advanced than their Russian counterparts, together with staggering quantities of ammunition and radars capable of quickly identifying the source of incoming fire. And there are brand new drones, developed with Ukraine’s specific needs in mind.

The primary purpose of all this is to allow Ukraine to withstand Russia’s attacks and prevent Moscow from taking more territory. But Western officials insist that Vladimir Putin must not be seen to succeed. At some point, that’s going to mean enabling Ukraine to go on the offensive.

The battle for the Donbas will make or break everyone’s plans. If Russia succeeds, then officials warn it may turn its attention, once again, to the Black Sea port of Odesa, and perhaps even Kyiv.

But if it fails, then Vladimir Putin’s whole Ukraine project will be in jeopardy. It could be weeks, even months, before we know which way it will go.

Image source, .

A new mass grave has been reported near Mariupol, the city mayor's adviser Petro Andryushchenko has said.

Writing on on Telegram, Andryushchenko said officials had received information about a "mass burial site of killed Mariupol residents in an attempt to conceal the traces of war crimes".

The BBC has not been able to independently confirm the claim.

Andryushchenko asked journalists to find photos of the grave on satellite images, saying it was located in Livoberezhnyy district near the Vynohradne village cemetery.

He added: "This proves once again that the occupiers are collecting and burying, or cremating dead Mariupol residents in every district of the city."

Anna Foster
Reporting from Kyiv

Dmitro is struggling to speak, a bandage pressed to his face. He doesn’t remember much about the moment his work van drove over a mine, just the huge noise in his head and ears, and the feeling of falling to the ground.

I joined a demining patrol on the outskirts of Kyiv and watched as they found unexploded shells and weapons lying in the grass by the roadside.

Some are blown up where they lie in a controlled explosion. Others are gathered and taken to a deep quarry outside the city. When they’re detonated, the black and grey mushroom cloud rises hundreds of metres into the sky.

As they begin to return home, people here are nervous and frightened about this new threat. Every day around 5,000 dangerous items are being neutralised.

The head of the Kyiv region bomb squad tells me the explosive remnants of just one month of fighting in these towns could take a whole year to clear away.

Image source, Reuters

The evacuation of about 100,000 people trapped in Mariupol will only succeed with the help of the UN, Ukraine’s deputy prime minister has said.

Iryna Vereshchuk told BBC Radio 4's The World Tonight the UN needed to become involved in arranging humanitarian corridors, saying it was the "only organisation with the capacity and strength to prevent death" but was so far "only observing events".

United Nations Secretary General António Guterres is to meet Russian President Vladimir Putin in Moscow on Tuesday.

Speaking before the visit was announced, Vereshchuk said "evacuation is only possible with the assistance of the UN. The UN and Guterres need to get involved and arrange corridors".

She said: "We have no time to wait. These corridors must be set up in the next few days."

Vereshchuk said the Ukrainian fighters in the besieged Azovstal steelworks in Mariupol "will not surrender - they will be fighting until the end. Until they remain there, Mariupol is part of Ukraine".

You can listen to the full interview on Radio 4’s The World Tonight at 22:00 BST.

Mariupol's Mayor Vadym Boychenko spoke to the BBC earlier and was asked about the reports of atrocities taking place in the besieged city.

Boychenko said: "There are already eyewitness statements from Mariupol citizens about the atrocities that they saw and are still seeing, unfortunately."

He said the number of people killed in Mariupol is frightening, and "over 20,000".

He added that satellite imagery from Maxar technologies shows mass graves and "there is some new evidence we obtained today from a different area".

He said that Russian troops are "destroying the city with its inhabitants" and they're doing it on purpose.

"They set this genocide up by closing the city down and using land artillery and airstrikes first, and then the ships that arrived later. The intent and the signs of a war crime and a genocide of the citizens of Mariupol," Boychenko said.

Thousands of tonnes of Ukrainian ammunition is now said to be in Russia's hands, after the capture of an arms depot in the Kharkiv region was claimed by the Russian military.

The Tass news agency reported the claim by the country's defence ministry and described the depot as large.

There was no independent verification of the news, although earlier in the day, Ukraine had said that Russian forces were trying to mount an offensive in the area.

In the city of Kharkiv itself, Ukraine said that Russian shells had struck a wedding hall and the main Barabashovo market, causing casualties.

Mohamed Madi
Reporting from Lviv

Image source, Russia's Ministry of Defence

Russia has released more images of missile launches from the Black Sea.

A video released by the Russian ministry of defence shows four high-precision Kalibr cruise missiles launched against “military infrastructure targets” inside Ukraine.

The ministry is trying to show that despite the sinking of the flagship cruisier Moskva last week, its Black Sea fleet still has the capability to strike targets deep inside the country.

But precision technology is no guarantee of precision strikes.

The five missiles that struck the western city of Lviv on Monday were also believed to be Kalibr-type rockets. But one destroyed a car-repair workshop, killing several workers inside who were having their morning coffee.

It’s not known where this latest series of attacks have landed or what casualties there are.

Image source, Reuters

More now on news that the United Nations Secretary General Antonio Guterres will visit Moscow on Tuesday to speak with Russian President Vladimir Putin.

The UN chief's associate spokesman, Eri Kaneko, said Guterres hoped to talk about what can be done to bring peace to Ukraine during his trip.

His office is also in touch with the Ukrainian government about a potential visit, Kaneko added.

The United Nations secretary general is to meet Russian President Vladimir Putin in Moscow on Tuesday, the Kremlin has said.

António Guterres will also have a working meeting and lunch with Foreign Minister Sergei Lavrov.

The next few weeks could be decisive for the war in Ukraine, a senior EU official has said, according to Reuters.

The official told reporters that Russia was likely to increase its military attacks in eastern Ukraine and along the country's coast.

"This is not a fairy tale with an imminent happy ending," they said.

"I think we are likely to see a very significant increase in the intensity of Russian military attacks in the east, I think we are likely to see an intensification of Russian military attacks along the coast.

"I think we will see the next couple of weeks as being decisive."

The Russian army is finalising identifying areas in the east of the country where it will launch its main strikes, the Ukrainian Defence Ministry has said, according to the Interfax-Ukraine news agency.

Ministry spokesman Oleksandr Motuzyanyk told a briefing Ukraine had come to this conclusion from "the nature of [Russian forces] fire, the formations of military units… and perpetual attacks in certain directions".

Motuzyanyk said the most intense Russian activity has been observed in the Izyum-Barvinkove direction, near Popasna, Severodonetsk, Mariupol and on the Zaporizhzhya-Donetsk road.

He added there are two Russian warships capable of carrying Kalibr cruise missiles in the Black Sea, with their combined salvo being 16 missiles.

Image source, .

Image source, Reuters

Pro-Russian forces have been seen on patrol in the Ukrainian port city of Mariupol.

Photographs, taken by the Reuters news agency on Thursday, show members of the Chechen special forces, and Russia's State Duma member Adam Delimkhanov, walking near the Azovstal steelworks.

Russian President Vladimir Putin said on Thursday that his troops had "liberated" Mariupol, but a contingent of Ukrainian fighters are still holding out in the underground bunkers of the complex, alongside hundreds of civilians.

Image source, Reuters

Image source, Reuters

Image source, Reuters

The UN's High Commissioner for Refugees says some 5,133,747 Ukrainians have fled the country since Russia's invasion on 24 February.

Today's figure is an increase of 48,387 from Thursday.

Women and children make up 90% of those who've left the country, it says.

Several countries have taken in Ukrainian refugees, but most have gone to Poland. Nearly six out of 10 people fleeing the country - 2,867,241 - went to Poland.

Image source, .

Jonathan Beale
Reporting from the Donbas region

One of Russia’s biggest pushes into the Donbas region appears to be coming from the north.

This morning we visited the town of Lyman, 22km (12 miles) north-east of Slovyansk, which had been targeted by Russian artillery and rockets overnight. There’ve been more throughout the day.

Lyman’s hospital has been hit and this morning the fire service battled a blaze. When we arrived in the morning it had been extinguished. Two rockets lay nearby on the ground, their casings still largely intact, but inside emptied of explosives. They appear to have contained cluster munitions.

Throughout the morning there was a steady drum beat of shelling - both incoming and outgoing around the town.

The threat of indiscriminate artillery strikes is making it harder and more dangerous to find out what’s happening on the frontline. But Russian forces have been making some slow advances from the north.

Image source, .

Damien McGuinness
Reporting from Berlin

Image source, Reuters

A few months ago, sending German tanks to a war zone would have led to public outrage. Today, German Chancellor Olaf Scholz is under fierce attack because he appears reluctant to do just that.

Some 55% of Germans say they want heavy weapons, such as tanks, sent to Ukraine, with 37% against.

Green and FDP politicians in his own government, as well as conservative opponents, accuse centre-left SPD Chancellor Scholz of putting a brake on weapons deliveries.

Berlin has delivered fewer weapons than the UK and the US, and was slower to respond. But Germany is not such an outlier compared to other western European countries, and pledges to pick up the pace, including with heavy weaponry.

Slovenia will now send Soviet-era tanks to Ukraine - which Ukrainian soldiers can operate and can be used straight away. In return, Berlin will give Slovenia German-made tanks, which need training.

Germany will also train Ukrainian soldiers to use German-made systems. And Berlin will give a billion euros to Kyiv to buy weapons.

The chancellor’s argument that Ukraine needs tanks that can be used straight away is reasonable. And because of decades-long low defence investment, Germany does not actually have that much to give.

Chancellor Scholz does not belong to that traditionally soft-on-Moscow wing of his party.

But it also might be that he’s nervous of losing the support of those SPD party members who still believe that sending too many weapons to Ukraine means escalating the war.

What UK's tanks announcement signifiespublished at 15:03 British Summer Time 22 April 2022

15:03 BST 22 April 2022

Frank Gardner
BBC News, Security Correspondent

Sending British main battle tanks to Poland, if confirmed, would be a very significant move.

As one senior British Army officer put it, it would raise the UK's commitment to Ukraine by a further notch but also increases the chances of Britain - and Nato - eventually becoming co-belligerents in this conflict.

The Ministry of Defence says Challenger 2 main battle tanks would be sent to Poland if the move gets the go-ahead - and these would be intended to "backfill" for the T72 tanks that Poland is sending directly to Ukraine. There are no plans to send British tanks or crews into action in Ukraine.

Until very recently Nato countries have been reluctant to supply heavy weaponry to the Ukrainians for fear of antagonising President Putin and risking an all-out European war that puts Nato forces into direct conflict with Russia.

But with each reported Russian atrocity that is revealed, notably in Bucha, these Western inhibitions have melted away.