Ukrainian President Volodymyr Zelensky has described the Russian invasion of his country as involving "the torture of the whole nation".

Speaking to CBS News through a translator on Sunday, Zelensky said the people of Ukraine did not want to be subdued by Russia and were being destroyed and exterminated as a result.

Asked directly whether Russia's actions constitute genocide, he said: "Indeed, this is genocide. The elimination of the whole nation and the people. We are the citizens of Ukraine. We have more than 100 nationalities.

"This is about the destruction and extermination of all these nationalities."

And in a later video address to the nation on Sunday night, Zelensky said "concentrated evil has come to our land", adding that "every crime of the occupiers on the territory of our state" would be investigated.

"Everyone guilty of such crimes will be entered in a special Book of Executioners, will be found and punished," he said.

While we await further information from what appears to be an attack on protesters in occupied Enerhodar, here's a bit more on Mariupol.

We've been telling you about today's renewed attempt by the Red Cross to reach the devastated city. But why does Russia consider the southern port so important?

If Mariupol falls, it would give Russia control of one of Ukraine's biggest ports and create a land corridor between Crimea and areas in Luhansk and Donetsk held by Russian-backed separatists.

Connecting Crimea with Russia via the rebel-held areas would make it much easier for Russia to move goods and people to and from Crimea. Russia has wanted this since 2014, after it annexed Crimea.

Currently, the peninsula is connected to Russia via a single bridge, built at great expense after the Russian annexation.

Image source, .

Russia's actions in Ukraine are a "playbook of what war crimes look like", Dr Michael Newton, a former senior adviser to the US Ambassador at Large or War Crimes has told the BBC.

The bodies found outside Kyiv are believed to be just the latest example. He said others seen perpetrated so far by Russia include:

• Intentional targeting of civilians
• intentional destruction of civilian property
• indiscriminate shelling
• starvation of a civilian population

Dr Newton also said while it was clear war crimes were happening at a "macro level", it was important also to look to a "granular level of specific preparation of specific cases against individuals".

He rubbished Russia's response that it hasn't targeted civilians during the war. Moscow on Sunday claimed the reports of bodies in the streets in Bucha and Irpin were fake.

Dr Newton said the Russians could say whatever they liked but "the evidence here is irrefutable".

The United Nations' human rights office says there have been 3,455 civilian casualties since the war in Ukraine began.

That includes more than 1,400 deaths and over 2,000 injuries.

The numbers are a conservative estimate and the UN believes the real figures are likely considerably higher.

The heaviest casualties continue to be reported from the Donetsk and Luhansk regions in the east, where Russia has battled with Ukraine over self-proclaimed independent republics it recently recognised.

If you’re just joining us, welcome. Here's a quick look at the latest lines:

• Ukraine has accused Russian troops of a "deliberate massacre", after hundreds of bodies were reportedly found in towns outside Kyiv in the wake of Russian troops’ withdrawal
• Western nations are now moving to impose more sanctions on Russia in response to the killings. The UK and France says they will also support an International Criminal Court investigation
• But Russia said no civilians had been hurt by their troops in Bucha and Irpin, claiming photographs from these towns were propaganda
• Meanwhile, as Russia pulled troops aways from the north, they renewed strikes on southern Ukraine, targeting Odesa and Kherson early Monday morning
• Russia’s assault on Mariupol in the south-east also continued, with heavy fighting in the city amid attempts to evacuate tens of thousands of trapped locals

With that, its Rebecca Seales in London signing off and handing over to my colleagues Yvette Tan and Frances Mao over in Singapore.

Image source, Getty Images

A taped video address from Ukraine's President Volodymyr Zelensky has just been played at the 64th annual Grammy Awards.

"Our musicians wear body armour instead of tuxedos," he said.

"They sing to the wounded in hospitals, even to those who can’t hear them. But the music will break through."

He told the crowd his country was fighting for "our freedom to live, to love, to sound" but Russian bombs were bringing silence to the streets.

"Support us in any way you can, but not with your silence," he told the crowd.

"Fill the silence with music."

Ukrainians have been sharing videos of their country before the war, which have gone viral on social media.

The BBC spoke to four women, who told us about those memories, and why they thought it was important to share them with the world.

They also spoke about their own experiences of the war.

Ukraine has evacuated 2,964 people from conflict zones in the port city of Mariupol and the nearby Luhansk region, Deputy Prime Minister Iryna Vereshchuk said on Sunday.

The Red Cross has made repeated attempts to gain access to Mariupol after being forced to turn an aid convoy around on Friday.

Ms Vereshchuk said talks with Russia to allow Red Cross buses access to the city itself were ongoing.

On Thursday she said about 75,000 people had been evacuated from Mariupol in recent weeks.

It was not immediately clear exactly where the evacuations announced on Sunday were made from, but many in recent days have been conducted with the use of humanitarian corridors.

Image source, Getty Images

Taking control of the city of Mariupol is "almost certainly a key objective of the Russian invasion", the UK's Ministry of Defence has said.

The MoD said troops would have a land corridor from Russia to the Russian-occupied Crimean peninsula if the besieged port city in the southeast of the country fell.

On Sunday, it again reported heavy fighting and indiscriminate shelling as Russian forces seek to seize the city.

But the MoD added that Ukrainian fighters "maintain a staunch resistance" and have retained control in key parts of the city.

Here's more on why Mariupol is so important to Russia's plan

The European Union should consider a ban on gas imports from Russia, German Defence Minister Christine Lambrecht has said.

It comes after alleged atrocities by Russian forces in the Ukrainian town of Bucha attracted widespread condemnation from world leaders.

Speaking to German public broadcaster ARD, Ms Lambrecht said: "There has to be a response. Such crimes must not remain unanswered."

German Chancellor Olaf Scholz also said Putin and his backers would "feel the consequences" of their actions.

Russia supplies around 40% of Europe's gas, a fact that has so far made Germany and other European nations reluctant to expand sanctions to target its energy sector.

Satellite images from Bucha show a 45-foot trench at a site where a mass grave has been identified, a US satellite data firm says.

Images captured on March 31 and released by Maxar Technologies show what appears to be a trench within the grounds of the Church of St. Andrew and Pyervozvannoho All Saints.

The company said signs of excavation could be seen in images taken as early as 10 March.

The BBC could not immediately verify the images, although a team from CNN reported seeing bodies in a mass grave at the site.

Image source, Maxar Technologies/Reuters

Image source, Reuters

As we've been reporting, there have been claims that Ukrainian civilians were indiscriminately killed as Russian forces retreated from the city of Bucha, near Kyiv.

Moscow is now demanding an emergency session of the United Nations Security Council on Monday 4 April.

Russia is a permanent member of the 15-member body.

Dmitry Polyansky, the country's UNSC deputy representative, said it was making the request "in light of the blatant provocation of Ukrainian radicals".

Since the start of its invasion more than five weeks ago, Russia has argued frequently with other members of the body, trading allegations of human rights abuses with the US in particular.

Reports are coming in of explosions late on Sunday in Ukraine's southern port of Odesa.

The authorities in the strategic city on the Black Sea coast are yet to confirm the reports by local media and a Reuters witness.

Odesa - where about one million people live - was hit by Russian missiles on Sunday morning.

A Ukrainian official said those missiles had struck "critical infrastructure", and there were no casualties.

Russia later said it had targeted oil facilities in the region that Ukraine was using to supply its troops.

Millions of people have fled Ukraine since the Russian invasion started on 24 February.

Among them were a number of foreigners, either living, working or studying in the country.

Korrine Sky, a British-Zimbabwean second-year medical student, is one of them.

Using Korrine's social media messages, photos and videos, we have pieced together her harrowing journey out of Ukraine, into an immersive mobile experience.

Image source, PA Media

No amount of disinformation from the Kremlin can hide the truth about the killing of civilians in Ukraine, UK Prime Minister Boris Johnson has said.

Images from the town of Bucha since the withdrawal of Russian forces have shown widespread destruction and bodies lying in the street, some with their hands tied behind their backs.

Similar pictures have emerged from the neighbouring town of Irpin.

Russia's defence ministry has denied that any civilians were harmed by its forces in Bucha and called the photos "another production of the Kyiv regime for the Western media".

Writing on Twitter, the prime minister said: "Russia’s despicable attacks against innocent civilians in Irpin and Bucha are yet more evidence that Putin and his army are committing war crimes in Ukraine.

"No denial or disinformation from the Kremlin can hide what we all know to be the truth – Putin is desperate, his invasion is failing, and Ukraine’s resolve has never been stronger."

Read the full story here.

Image source, Getty Images

If you're just joining us, or need a recap, here's the latest we have on the alleged massacre of civilians by Russian forces in the Ukrainian city of Bucha.

Bucha 'massacre'

• There have been claims of indiscriminate killings as Russian forces retreat from key battleground areas near the capital Kyiv
• Ukraine's foreign minister has accused Russian troops of a "deliberate massacre" in Bucha town, near Kyiv
• Pictures from the city show widespread destruction and bodies lying in the streets
• The BBC's Jeremy Bowen reports that Ukrainian troops found at least 20 dead men, some with their hands tied behind their backs, as they entered the town
• Ukrainian prosecutors say they have found 410 bodies in several towns near Kyiv

Severe condemnation

• World leaders have condemned the killings
• UK Prime Minister Boris Johnson said the killings were "yet more evidence" that Russia was committing war crimes in Ukraine, while US Secretary of State Antony Blinken described the scenes as a "punch to the gut"
• Germany's vice chancellor called the killings a "terrible war crime" and France's president said pictures from Bucha were "unbearable"

Russia responds

• In a statement, Russia's defence ministry denied that any civilians had been harmed by Russian forces in Bucha
• They call photos from the town "another production of the Kyiv regime for the Western media"

Image source, Getty Images

While we've been reporting about claims of a massacre in the town of Bucha, one civilian arriving at Lviv train station from Kharkiv relayed graphic scenes in that city's suburbs.

Speaking about corpses seen in the town of Bucha, the man, who gave his name as Andre, told the BBC: "In these pictures, there are bodies. In the Kharkiv suburbs, there are only parts of bodies: legs, arms, heads."

Kharkiv, in the north east, is partially surrounded by Russian forces and the city has suffered relentless shelling.

A regional prosecutor said on Sunday that seven people had been killed in shelling in Kharkiv.

Ukrainian President Volodymyr Zelensky has described the Russian invasion of his country as involving "the torture of the whole nation".

Speaking to CBS News through a translator, Zelensky said the people of Ukraine do not want to be subdued by Russia and are being destroyed and exterminated as a result.

Asked directly whether Russia's actions constitute genocide, he says: "Indeed, this is genocide. The elimination of the whole nation and the people. We are the citizens of Ukraine. We have more than 100 nationalities.

"This is about the destruction and extermination of all these nationalities."

Image source, Getty Images

United Nations Secretary-General António Guterres has called for an independent investigation into alleged killings in Bucha - the town near Kyiv where bodies were found discarded on a road.

Writing on Twitter on Sunday, he said: "I am deeply shocked by the images of civilians killed in Bucha, Ukraine.

"It is essential that an independent investigation leads to effective accountability."

A statement released by the United Nations Human Rights Office also raised the possibility that Russia had committed war crimes in Ukraine.

"What is known to date clearly raises serious and disturbing questions about possible war crimes and grave violations of international humanitarian law," it read.

It said it was important that all bodies be exhumed and identified "so that relatives can be informed, and that the exact cause of death be established to help ensure accountability and justice".

A number of people have been killed in Russian shelling of the city of Kharkiv on Sunday, the regional governor says.

In a statement on Telegram, Governor Oleh Synyehubov said: "In the evening, the occupiers shelled the Slobidsky district of Kharkiv.

"Unfortunately, there are dead and wounded among the civilian population.

"As of this time, there are 23 casualties, including children. The figures are being established."

Kharkiv is Ukraine's second-biggest city and is situated close to the border with Russia.