Image source, EPA

If you're just joining us or if you need a catch-up, here are the latest developments in Ukraine:

• Ukraine's President Volodymyr Zelensky said in a late-night address that Russia's aggression was never limited to just Ukraine and its target is "the whole European project"
• Zelensky urged the West to impose a complete embargo on Russian energy products and to supply Ukraine with additional weapons
• He said Ukraine is ready for a tough battle, as Russian forces were massing in the east of the country
• Zelensky has held a phone call with German Chancellor Olaf Scholz in which they discussed the possibility of additional anti-Russian sanctions, defence and financial support for Ukraine
• Ukraine's Deputy Prime Minister Iryna Vereshchuk says Kyiv has agreed nine humanitarian corridors to help people escape heavy fighting in the east of the country
• Pope Francis has called for an Easter truce in Ukraine, leading to negotiations and peace
• Military officials in Britain say that Moscow is recruiting soldiers discharged from military service up to 10 years ago in response to growing losses

Image source, Reuters

During his visit to Kyiv on Saturday Boris Johnson praised the resilience of Ukrainian rail workers when he took the train to the capital from Poland.

The UK prime minister said the workers' nickname the "iron people" reflected their spirit in "standing up to the appalling aggression that we are seeing".

His comments came a day after an attack on the train station in the city of Kramatorsk saw 52 people killed as they awaited evacuation.

Johnson said: "I am so sorry for the loss of some of your colleagues and comrades in Kramatorsk.

"I want to say a massive thank you to all the staff of Ukrainian railways for what you're doing."

Earlier we reported that Ukraine said it discovered another mass grave near Kyiv, in the village of Buzova.

A Ukrainian official has since told the Reuters news agency that at least two civilian bodies have been found at the site.

"There are other people who we cannot find," said Taras Didych, head of the Dmytrivka community that includes Buzova.

"They could be in different places, but this doesn't lessen the pain of the loss of loved ones," he added.

There's been no independent confirmation, but several mass graves have so far been found in areas around the Ukrainian capital previously occupied by Russian troops.

There's been international condemnation of Moscow over alleged war crimes, but Moscow denies targeting civilians.

Ukrainian President Volodymyr Zelensky said he's had a phone call with German Chancellor Olaf Scholz in which they discussed the possibility of additional anti-Russian sanctions, defence and financial support for Ukraine.

Zelensky posted on social media, external that their discussion "emphasized that all perpetrators of war crimes must be identified and punished".

Separately, Zelensky's office said in a statement the president had held a conference call with Ukrainian officials during which Kyiv's proposals for a sixth package of European Union sanctions had been developed.

Image source, Reuters

Pope Francis has called for an Easter truce in Ukraine, leading to negotiations and peace.

"Put the weapons down!", he said at the end of a Palm Sunday service for tens of thousands of people in St Peter's Square at the Vatican.

"Let an Easter truce start," he said.

"But not to rearm and resume combat but a truce to reach peace through real negotiations."

The head of the International Committee of the Red Cross in Ukraine said his team was unable to reach the besieged port city of Mariupol last week despite trying for five days.

Pascal Hundt told Sky News the security conditions were not good which led to the team turning around 20km from the southern city.

He said they collected refugees on the way and private cars joined the convoy under the Red Cross flag, with more than 1,000 people finally reaching Zaporizhzhia.

Many more similar operations will need to take place in the coming days and weeks, he said, adding that the organisation was in touch with Russian and Ukrainian authorities to ensure safe passage was agreed.

The deadly missile attack on a railway station at Kramatorsk on Friday had also made things more difficult with many people using private cars rather than trains, he said.

Two people have been killed and several injured in the Ukrainian town of Derhachy in the north-eastern Kharkiv region, local governor Oleh Synyehubov said in a Facebook post.

He added that Russian forces had carried out 66 artillery attacks across several regions.

"Two people were killed, there are casualties,” Synyehubov said. “As you can see, the Russian army continues to 'fight' with the civilian population, because it has no victories at the front.”

The BBC has not been able to confirm this independently.

The UK could impose sanctions on Russian troops and generals suspected of committing war crimes, policing minister Kit Malthouse says.

He tells Sky News' Trevor Phillips evidence of atrocities should be gathered as "assiduously as possible" during the conflict.

"While that is ongoing we can take action domestically around sanctions we are able to put on individuals, including combatants, leading generals and others involved in it, to signal our recognition of their part in this dreadful, dreadful assault upon a free democratic country," he says.

Labour's shadow home secretary describes delays in Ukrainian refugees getting UK visas as "a total nightmare" and says her party would only apply security checks to those coming.

Yvette Cooper tells BBC One's Sunday Morning programme that it is "totally shameful" that only 1,200 people have arrived under the Homes for Ukraine scheme despite 200,000 people offering to house a refugee.

She says security checks can be done within hours if not on the spot and says Labour believes they are sensible and do not delay anyone coming.

But she says at the moment people are having to prove where they lived on 1 January.

Policing minister Kit Malthouse says progress admitting Ukrainian refugees to the UK has been disappointing but says it is "motoring" now.

"I know that people are disappointed with the progress of the visa regime. The home secretary has been out this week expressing her frustration and regret that it hasn't been quicker now," he told Sky News.

Here's how the UK's schemes for Ukrainian refugees work.

Ukraine says it's discovered another mass grave near Kyiv, after Russian forces withdrew from areas north of the capital to focus their assault on the east.

According to the Reuters news agency, an official in the village of Buzova said the bodies of dozens of civilians were found in a ditch near a petrol station.

There's been no independent confirmation, but a number of mass graves have so far been found in areas around Kyiv.

The Russian army had occupied the area for weeks while surrounding the Ukrainian capital.

There's been international condemnation of Moscow over alleged war crimes. Moscow denies targeting civilians.

Ukrainian President Volodymyr Zelensky has said that Russia's aggression is not limited to Ukraine, and that the whole of Europe is a target.

In his late-night address on Saturday, he said the use of force by Russia was a "catastrophe that will inevitably hit everyone".

Boris Johnson's visit to the Ukrainian capital Kyiv was "very timely and very important", an adviser to the Ukrainian president says.

Ihor Zhovkva, senior diplomatic adviser to President Volodymyr Zelensky, says that the UK prime minister "did not come empty handed", with the pair discussing various types of support the UK could offer.

This included anti-ship missiles as well as financial support.

Zhovkva tells BBC One's Sunday Morning that the anti-ship missiles would help defend cities like Odesa which were being fired upon by Russian warships.

He says Ukraine needs "weapons, weapons and more weapons" to continue the fight against Russia.

Catherine Byaruhanga
BBC News, Odesa

Image source, Reuters

Residents of the southern coastal city of Odesa are observing a weekend curfew after authorities warned of a possible missile strike.

There have been at least three explosions reported in and around the city since a rocket struck an oil facility on the outskirts of Odesa, eight days ago.

The regional administration has ordered people to stay indoors, starting at 21:00 local time on Saturday evening till 06:00 Monday morning.

Shops, restaurants, and businesses are closed, and no one is allowed on the streets without a special pass.

Sunday should have been a day to celebrate here as the city marks 78 years since it was liberated from Nazi occupation during World War Two. Back then Russian forces helped to save people here, now they threaten to do the very opposite.

Odesa has been under threat from Russian naval ships in the Black Sea that launch rockets towards the city and could stage an amphibious landing.

UK Prime Minister Boris Johnson has promised to donate anti-ship missile systems to Ukraine to help fend off the fleet.

Despite having held back Russian forces up until now – the mood in Odesa is sombre and tense on this Remembrance Day. Many are unclear about what Russia’s plans are for this historic city.

Ukraine's Deputy Prime Minister Iryna Vereshchuk says Kyiv has agreed nine humanitarian corridors to help people escape heavy fighting in the east of the country.

"All the routes for the humanitarian corridors in the Luhansk region will work as long as there is a ceasefire by the occupying Russian troops," Vereshchuk says, in a statement on her Telegram channel.

Earlier the region's governor Serhiy Gaidai wrote on Telegram that there would be nine trains on Sunday for residents to get out on.

UK Prime Minister Boris Johnson made a surprise visit to Ukraine's capital and met President Volodymyr Zelensky yesterday. They walked through Kyiv's streets together and met a passer-by.

Johnson's last minute visit to the capital was unannounced - the first sign he was there came with a tweet by the Ukrainian embassy in London showing a photo of him meeting President Zelensky.

Downing Street said the PM travelled to Ukraine in an attempt to show solidarity with Ukrainian people.

Image source, Reuters

In an interview with The Sunday Telegraph, external, Nato's General Secretary Jens Stoltenberg says the alliance is "in the midst of a very fundamental transformation" that will reflect the "long-term consequences" of Vladimir Putin's war in Ukraine.

In the interview, Stoltenberg says Nato is planning for a permanent military presence on its border in an effort to battle future Russian aggression.

He tells the paper his focus is on ensuring other Nato allies meet the alliance's minimum requirement of 2% expenditure as a share of their GDP.

The UK's Ministry of Defence says that in response to "mounting losses" Russia is seeking to bolster troop numbers with personnel discharged from military service since 2012.

It says efforts to increase manpower include trying to recruit from the unrecognised Transnistria region in Moldova.

Moscow has not confirmed how many soldiers had been killed since the invasion began but last week Kremlin spokesman Dmitry Peskov admitted Russia had suffered "significant losses of troops".

Western leaders believe that between 7,000 and 15,000 Russian soldiers have been killed.

Image source, Reuters

If you're just joining us, here's a round-up of what's been happening.

• British Prime Minister Boris Johnson made a surprise visit to Ukraine's capital, Kyiv. In a statement released after the visit, he praised Ukrainian President Volodymyr Zelensky's "resolute leadership and the invincible heroism and courage of the Ukrainian people". The UK said it will provide an additional 120 armoured vehicles and new anti-ship missile systems to Ukraine
• The EU has reopened its embassy in the Ukrainian capital, Kyiv, having temporarily moved it to Poland after Russia's invasion of Ukraine
• An exchange of prisoners took place between Russia and Ukraine: 12 military personnel and 14 civilians were released
• Mr Zelensky said Ukraine is preparing for an important battle in the East
• The bodies of 10 civilians were recovered from under rubble in the destroyed city of Borodyanka, near Kyiv on Saturday, said the deputy head of the Ukrainian emergency service in the Kyiv region, Bogdan Danilyuk
• The governor of Donetsk in eastern Ukraine, Pavlo Kyrylenko, said five people have been killed in shelling in the region - he said four were killed in Vuhledar and one in Novomykhailivka
• On Saturday, the UK's Ministry of Defence said that Russia's withdrawal from the north revealed mass graves and the use of human shields
• Eastern Ukraine's biggest football club, Shakhtar Donetsk, have opened what they're calling their "Football for Peace" tour with a friendly match in Greece against league leaders Olympiakos. The charity tour is raising money to provide aid for people affected by the war in Ukraine

Frank Gardner
BBC Security Correspondent

Image source, Getty Images

Nato ministers have been meeting in Brussels this past week to discuss how far they should go in providing military equipment to Ukraine.

The challenge for Nato throughout this war has been how to give its ally Ukraine enough military support to defend itself without getting drawn into the conflict and finding itself at war with Russia.

The Ukrainian government has been explicit in its calls for help.

If it is to have any chance of fending off the coming Russian assault on the Donbas region in the east of the country, it says, then it urgently needs a resupply of the West's Javelin, NLAW (next-generation light anti-tank weapon), Stinger and Starstreak anti-tank and anti-aircraft missiles that its forces have already been using to such effect in this war.

That much is coming. But Ukraine wants more.

It wants tanks, warplanes, drones and advanced missile air defence systems to counter Russia's increasing use of air strikes and long-range missiles that are steadily depleting Ukraine's strategic stores of fuel and other essentials.

So what exactly, many people may ask, is holding Nato back?

The answer is escalation.

Read more here.

Image source, EPA

Ukrainian President Volodymyr Zelensky said during his late-night address on Saturday that Russia's aggression was never limited to just Ukraine and the whole of Europe was a target.

Mr Zelensky urged the West to impose a complete embargo on Russian energy products and to supply Ukraine with additional weapons.

He said Russia's use of force was "a catastrophe that will inevitably hit everyone".

Mr Zelensky said Ukraine is ready for a tough battle, as Russian forces were massing in the east of the country.

But he added: "This will be a hard battle, we believe in this fight and our victory. We are ready to simultaneously fight and look for diplomatic ways to put an end to this war."

Ukrainian negotiator Mykhailo Podolyak said President Zelensky and Russian President Vladimir Putin would not meet until after Russia was defeated in the east.