Thank you for joining our live coverage today. We'll leave you with the latest developments in the war in Ukraine:

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Over 20,000 Russian troops may have been killed during the Ukraine conflict, says retired US General David Petraeus. This is "many multiples of what they lost in nine years inAfghanistan", he says. Russia's last estimate of its troop losses was 1,351, given on 25 March.

This war is approaching 100 days duration.

Speaking to the BBC, he says he's not surprised by Ukraine's ability to repel Russian forces. Ukraine "performed above even the highest of expectations most of us had".

On Russia's effectiveness in the war, Petraeus is very critical: "No one predicted Russia's sheer incompetence, at every single level," he says.

However, on Severodonetsk he is less upbeat about Ukraine's situation: "At some point, the Ukrainians may have to withdraw to fight another day."

And Russia seizing the city would be significant in the psychological "war of ideas", says Petraeus.

He is sceptical about Russia's offer to escort cargo ships of wheat out of Ukrainian ports. "They said they would do that if we lift the sanctionsand there's no way that we're going to lift the sanctions," he says.

And any idea of Western forces sending in ships to force a way through the Black Sea is "dead on arrival", he says, because " you're going to sail into a direct conflict with Russia".

James Waterhouse
Reporting from Poltava

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Hlib Stryzhko endured psychological torture and was denied medical treatment for a broken pelvis and jaw. Yet somehow, he made it home.

In a hospital bed in the Ukrainian city of Poltava, he tried to sit up.

The 25-year-old soldier's pelvis was supported by metal scaffolding - one of his many injuries sustained while trying to defend Mariupol, nearly 500km (310 miles) to the south.

As his mother Olesya helped him he grimaced with pain, but seemed eager to share his story nevertheless.

"Turning my head, I saw that a tank was aimed at me," he recalled.

"When a tank fires, there is no time between exit and arrival. It happens instantaneously. I saw a bright flash."

Image source,UKRAINIAN PRESIDENTIAL PRESS SERVICE

Ukraine's forces have had some success near the southern city of Kherson and are advancing in parts of the Kharkiv region to the east of Kyiv, Ukrainian President Volodymyr Zelensky says, Reuters reports.

Zelensky praised his military's "utmost courage" and says they "remain masters of the situation at the front".

The Ukrainian president did however say Russian forces have a "significant advantage" in terms or equipment and numbers.

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Ukrainian officials are reporting a "shutdown of all communications" in the Russian-occupied southern region of Kherson, Reuters reports.

An unspecified intrusion "by the occupation regime" has taken place, with equipment powered down and cables disconnected, Ukraine's State Service for Special Communication and Information Protection has said, according to Reuters.

This has left residents "without Ukrainian mobile communication and Internet access" and "no means to make national and international phone calls using landline phone devices," the agency has reportedly said.

The BBC has not been able to independently verify this.

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Image source,AFP

The 97th day of the war saw Ukrainian and Russian forces battling for control of the eastern city of Severodonetsk, which is said to be divided between the two sides.

Up to 15,000 people may still be trapped there, Luhansk regional governor Serhiy Haidai has said.

Both sides are suffering heavy casualties and the Ukrainian command may decide a tactical retreat would better serve their medium-term interests.

Anna Holligan
BBC News, The Hague

Image source,Reuters

Today was described as “amomentous day” by the International Criminal Court (ICC) prosecutor, KarimKhan.

Russian naval vessels have escorted the first cargo ship to leave the Port of Mariupol since Russia took control of the area.

In footage released by the Russian Defence Ministry, artillery boats can be seen flanking the ship as it left the port, reportedly carrying metal in its hold.

It's the first ship to enter and then leave the port, on the Sea of Azov, since the fighting in Mariupol ended.

Earlier, Russia's Foreign Minister Sergey Lavrov said the Russian Navy is ready to provide safe passage to ships transporting grain currently stuck in Ukraine's ports - if Ukraine clears coastal waters of mines.

Lavrov said: "If this de-mining problem is solved... the Russian Federation will ensure the unhindered passage of these ships to the Mediterranean Sea and further to their destinations."

The explosion of a nitric acid container in Severodonetsk is thought to have been caused by an airstrike, Luhansk's regional governor Serhiy Haidai says.

“Therewas allegedly an airstrike on the chemical plant in Severodonetsk which hitthe tank with the remains of nitric acid", he says.

He tells the BBC toxic fumes were released into the air. Based on a previous chemical leak, he predicts there might be a threat to people within a 400-metre range of the explosion. Outside of that range, people might experience some eye irritation, he says.

At the moment there is no possibility of evacuating any of the 15,000 residents who remain in Severodonetsk - as it comes under sustained attack from Russians, he says. "Russians provide no humanitarian corridors," he says.

"Seventy to eighty percent of the city is controlled by the Russian army. The neighbouring city of Lysychansk isunder the full control of Ukraine”, he adds.

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The head of the Severodonetsk state district, in the Luhansk region, says the city is "the hottest spot in Ukraine right now".

Speaking to the BBC, Roman Vlasenk says Russia has "thrown everything at it".

Delays to military aid from Europe and the US, such as anti-tank weapons, is a particular problem, he adds, with civilian evacuation and humanitarian aid delivery impossible.

In terms of personnel on the ground, Vlasenko says they have parity with Russia. However, he says Russia "has more aviation and artillery" which is preventing them from being able to defend against Russian forces or launch counter-offensives.

More now on reports of a chemical explosion in Severodonetsk.

A container withchemicals has been blown up at the Azot chemical works in the city, the Russian news agency TASS says.

It quotes the “ambassador” of the self-proclaimed Luhansk People’s Republic Rodion Miroshnik, writing on his Telegram channel, that a container "has been blown up", and the plant "is still controlled by the Ukrainian regime’s armed units".

The plant is one of Ukraine’s biggest chemical works, and pre-war, it has been employing around 7,000 people, according to TASS.

It's thought to manufacture acetic acid, methanol and vinylacetate.

Image source,Luhansk military administration/Telegram

Local residents in the frontline city of Severodonetsk, in Luhansk, have been warned not to leave bomb shelters and urged to prepare masks to protect themselves against toxic fumes.

A nitric acid tank has been hit by a Russian airstrike, Luhansk governor Serhiy Haidai has said on messaging app Telegram.

He also posted photos of a large pink cloud over residential buildings in the city.

The key eastern city of Severodonetsk has seen intense fighting in recent days as Russian forces attempt to capture the city.

It’sjust gone 8pm in Severodonetsk, the eastern Ukrainian city in the Donbas regionthat is coming under extreme bombardment by Russian forces.

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A former defence minister to Ukraine has said his country can win the war with more weapons from the West.

"As soon as we can get more weapons, particularly those artillery weapons which are being shipped right now from the West, we can go to counter-offensive," Andriy Zagorodnyuk told the BBC.

He said Russian forces were "at maximum capacity" and were throwing everything at the fight in the Donbas.

"They're bringing all their equipment and so on - and so currently they are at maximum of their capacity, maximum of their capability."

"Ukraine is definitely not changing our strategy. We are absolutely determined to win. We know that we can. We know that our army is much more efficient and effective than Russia's.

"The only thing we need is to re-equip ourselves with additional weapons and we can do this."

Damien McGuinness
Reporting from Berlin

Image source,REUTERS/Christian Charisius

German Chancellor Olaf Scholz has announced his country will allow modern German-made tanks to backfill Soviet-era tanks sent from Greece to Ukraine.

Berlin already has similar deals with a number of countries that have Soviet-era tanks, which can be used by Ukrainian soldiers straight away without training.

So far, Germany has struck such deals with Slovakia, the Czech Republic and Poland.

Germany is also training Ukrainian soldiers in Germany on modern heavy weapons, which will then be delivered to Ukraine.

German ministers say Berlin is delivering a lot of weapons to Ukraine and dispute the impression abroad that Germany is not doing enough.

But some ministers and leading politicians within the government accept deliveries are slower and more complicated than originally hoped.

There is growing pressure in Germany for deliveries to be sped up, to be more transparent and better organised.

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Earlier we told you that Ukraine's chief prosecutor had said her officials had identified more than 600 Russian war crime suspects and had started prosecuting around 80 of them.

Iryna Vanediktova had been meeting the prosecutor of the International Criminal Court Karim Khan, and the pair gave a news briefing afterwards.

Karim described Ukraine as a crime scene, and said the tribunal was carrying out its largest ever investigation there, with plans to open an office in Kyiv in the next few weeks.

As things currently stand, the ICC can’t prosecute the crime of aggression because neither Russia nor Ukraine are in its list of members. However, the court is taking part in a joint investigation alongside Ukraine, Poland and Lithuania.

Nearly seven million people have fled Ukraine since the Russian invasion began on 24 February, latest figures show.

More than half of them - 3.6 million - have fled to neighbouring Poland, while nearly one million have relocated to Romania and Russia respectively.

Some of those who fled Ukraine, have returned home or to different parts of their country.

Image source,Reuters

BBC News Russian has compiled a list naming 3,052 Russian soldiers who have been killed in the current war in Ukraine.

The list is part of an ongoing investigation into the number and nature of Russian losses and is based on open sources, as well conversations with the families of those killed.

BBC journalists discovered fresh graves at 11 cemeteries located in different parts of Russia. Not all of them were marked as soldiers who died fighting in Ukraine, but the photographs of men in uniform, as well as wreaths bearing ribbons inscribed with 'From the Ministry of Defence' are tell-tale signs.

There is a continuing trend of a high proportion of officers among those killed - around 20%.

The findings match claims made by UK intelligence services, who stated this week that Russia was bearing “crushing losses” among junior and senior officers.

Russia's most recent casualty figures, released by Moscow on 25 March, claim 1,351 soldiers have been killed so far in the conflict.

Meanwhile UK intelligence estimates that, by the end of May, Russia had lost around 15,000 soldiers, while Ukraine puts the figure at around 30,000 killed.

As we've been reporting, the European Union has agreed to block all imports of Russian oil arriving by sea by the end of the year.

However, the EU will continue temporarily to allow imports by pipeline because Hungary imports 65% of oil via Russian pipelines and says its economy could not take the hit if that stopped.

Two other countries which import large amounts of Russian oil by pipeline, Germany and Poland, say they will stop doing so by the end of this year.

The EU says, overall, the new measures will cut oil imports from Russia by up to 90%.