Hundreds of mourners have gathered in Kyiv to say their goodbyes to a young Ukrainian activist who was killed in battle on the frontline.

Roman Ratushnyi, 24, died on Saturday while fighting Russian troops in Izium, which has been subjected to relentless shelling, according to Associated Press.

He was among the demonstrators who had helped topple the country’s pro-Russia leader in 2014, and did not hesitate to take up arms when Vladimir Putin launched his invasion in February.

Ukraine’s foreign ministry was among those to pay tribute to Ratushnyi, tweeting:

From the first day of Maidan, 17yo Roman joined the protests and was among the students beaten by police. At his 24 he decided to defend Ukraine from Russians.

We will always remember our brave defenders.

Several hundred potential war crimes committed by Russian troops in Ukraine are being investigated by German authorities.

Its federal police says it has received leads in the triple digits involving both political and military officials, reports AFP.

“Our clear goal is to identify those responsible for atrocities, to prove their actions through our investigations and bring them to justice,” its head, Holder Muench, told Welt am Sonntag newspaper.

German investigators could be sent to Ukraine, he added, but they would need an international mandate to do so.

Ukraine last month declared 15,000 suspected war crimes had been reported since the war began.

Chief prosecutor Iryna Venediktova said some 600 suspects had been identified, and included “top military, politicians, and propaganda agents of Russia”.

Russia has denied targeting civilians or involvement in war crimes.

Lithuanian authorities have said a ban on the transit through their territory to the Russian enclave of Kaliningrad of goods that are subject to EU sanctions will take effect from Saturday.

News of the ban came on Friday, through a video posted by Kaliningrad’s governor, Anton Alikhanov, Reuters reported.

The EU sanctions list includes coal, metals, construction materials and advanced technology, and Alikhanov said the ban would cover about 50% of the items that Kaliningrad imports.

Its immediate start was confirmed by the cargo arm of Lithuania’s state railways service in a letter to clients following “clarification” from the European Commission on the mechanism for applying the sanctions.

The British prime minister has urged the European Broadcast Union (EBU) to reverse its decision to move the Eurovision song contest from Ukraine to the UK.

The EBU decided to move the popular contest from Ukraine citing security risks and is currently in talks with the BBC.

Oleksandr’s war lasted only a week. The 36-year-old, a Ukrainian electrician working in Gdansk, hurried back to join up after Russia invaded and was deployed on 10 May to guard a chest-high trench in Donbas against the odds.

“We were shelled constantly during the day. There was not 10 minutes without Russian shelling,” he said, describing a fearful human cost. “Every day one person was killed and another couple wounded. Big losses, really big losses.”

On the seventh day, 16 May, it was over. A Russian drone had hovered over Oleksandr’s position near Avdiivka and, armed with the location, the invaders hurled one shell, then another, closer, and finally a third, closer still.

It felt as if he had been “hit by a stone” in his right arm, Oleksandr said, but it was worse: “I looked at my sleeve and then I tried to move my hand. It was just hanging.” Hastily he applied a tourniquet and sought refuge behind the lines.

Boris Johnson has said it is important for the UK to show it stands steadfastly Ukraine amid what he described as ‘Ukraine fatigue’.

Rockets hit a southern district of Ukraine’s central city of Kryvyi Rih on Saturday leading to at least two casualties, local authorities said in posts on messaging app Telegram.

The attack came as it was confirmed that the Ukrainian president, Volodymyr Zelenskiy, had visited the southern city of Mykolaiv during a working trip to the region, Reuters reported.

His office announced the trip in a statement on Saturday, without specifying when the visit took place.

“The president inspected the building of the Mykolaiv regional state administration which was destroyed as a result of a missile strike by Russian forces,” it said.

In the early hours of 24 February, Olena Zelenska became aware of the sound of muffled booms somewhere in the distance. As she drifted towards wakefulness, she realised the sounds she was registering could not be fireworks. Her eyes snapped open; she discovered she was alone in the bed. She jumped up and hurried to the next room, where she found her husband, the Ukrainian president, Volodymyr Zelenskiy, already dressed for work in a suit and tie.

“What’s going on?” she asked him.

“It’s started,” he told her.

Ukraine can and should host the 2023 Eurovision song contest, the British prime minister, Boris Johnson, said on Saturday, after the organisers said they were in talks to hold it in Britain instead due to the war.

While decades-long tradition dictates that the winner of the contest gets to host it the following year, organisers said the security guarantees required to hold the competition in Ukraine meant discussions would be held with the runner-up, Britain.

“Of course I would love it to be in this country but the fact is they won and they deserve to have it and I believe they can have it and I believe that they should have it,” Johnson told reporters on arrival back in Britain after a visit to Kyiv.

“I believe that Kyiv or any other safe Ukrainian city would be a fantastic place to have it,” he added. “It is a year away, it is going to be fine by the time the Eurovision Song Contest comes round and I hope the Ukrainians get it.”

The comments by organiser the European Broadcasting Union on Friday that it was in discussions with British broadcaster the BBC to host the next event was greeted with disappointment in Kyiv, which demanded further negotiations.

It is important Britain continues to show it is supporting Ukraine for the long haul, the prime minister, Boris Johnson, said on Saturday, warning of a risk of “Ukraine fatigue” as the war drags on.

“The Russians are grinding forward inch by inch and it is vital for us to show what we know to be true which is that Ukraine can win and will win,” Johnson told reporters on his arrival back in Britain from a visit to Kyiv.

Some members of his Conservative party had criticised him for making the trip instead of attending a conference in northern England, Reuters reported.

“When Ukraine fatigue is setting in, it is very important to show that we are with them for the long haul and we are giving them the strategic resilience that they need,” Johnson said.

I’m Tom Ambrose and I will be with you until 6pm UK time today.

Almost 100 miners have been trapped in a coal mine in Donetsk after power to the pit was cut.

Russian state news agency RIA blamed the incident on Ukraine, accusing it of launching attacks in the eastern region causing the power failure, according to Reuters.

“As a result of shelling [by Ukrainian forces], power to the Zasyadko mine in Donetsk was cut off, and 77 miners remain underground,” RIA said.

Reuters could not immediately verify the report, and there was no immediate reaction from Ukraine.

A banner declaring “Glory to Ukraine” has appeared at the King’s College Chapel at the University of Cambridge.

The sign of support, which reads “Slava Ukraini”, appeared alongside the country’s flag, and was tied between two spires of the church.

King’s College suggested the instalment would be removed from the 80ft historic building, but shared its concern for the those impacted by Russia’s war in Ukraine.

A spokesman said:

The King’s community is appalled by the suffering and loss of life inflicted by the Russian military across Ukraine in recent months, and the disastrous effect the hostilities are having on the lives of thousands of people, including displaced students and scholars,

While we regret the risks associated with the installation of a banner hung between the spires of the chapel, both in regard to the physical fabric of the historic building, and to the dangers now posed to those required to remove it, we are fully supportive of its sentiment.

Since the invasion we have been providing assistance to researchers stranded by the outbreak of war, as well as recently appointing the first of three displaced scholars to postdoctoral positions within the College, and establishing a fund for refugee students from all areas of conflict.

A Ukrainian medic who smuggled footage out of the besieged city of Mariupol has been freed by Russian troops three months after being captured.

Yuliia Paievska, known as Taira, used a bodycam to record her team’s efforts tending to the injured, including both Ukrainian and Russian soldiers, reports Associated Press.

The day before she was captured she handed the clips over to the agency’s reporters, one of whom fled the city with it embedded in her tampon.

Taira and a colleague were then taken as prisoners by Russian forces on 16 March, the same day an airstrike hit a theatre, killing 600 people.

“It was such a great sense of relief. Those sound like such ordinary words, and I don’t even know what to say,” her husband, Vadim Puzanov, said.

The Ukrainian president, Volodymyr Zelenskiy, on Friday night confirmed the medic was home, adding work would continue to “liberate everyone”.

Russian gas producer Gazprom said its supply of gas to Europe through Ukraine via the Sudzha entry point was seen down to 41.4m cubic metres on Saturday, from 41.9mcm on Friday.

Reuters reported Gazprom as saying an application to supply gas via another major entry point, Sokhranovka, was rejected by Ukraine.

Russia has probably renewed its efforts to advance south of Ukraine’s eastern city of Izium in the past 48 hours, Britain’s defence ministry says.

Russia’s goal was to penetrate deeper into the Donetsk region and envelope the pocket around the embattled city of Sievierodonetsk from the north, it said on Twitter on Saturday.

Reuters reported the ministry adding that if trapped Ukrainian civilians did not take up an offer of leaving via a corridor, Russia was likely to claim justification in making less of a distinction between them and any Ukrainian military targets in the area.

Hello and welcome to our continuing coverage of the war in Ukraine. It’s approaching 10am in Kyiv and these are the latest developments.

• A Ukrainian paramedic has been released from Russian captivity, the Ukrainian president, Volodymyr Zelenskiy, announced on Saturday. He said Ukraine had been able to secure the release of Yulia Payevska, a civilian paramedic who was captured by Russian forces in Mariupol on 16 March.
• The Ukrainian president, Volodymyr Zelenskiy, tweeted that the bravery of Ukrainians had created the opportunity for Europe to “create a new history of freedom, and finally remove the grey zone in Eastern Europe between the EU and Russia”. In his nightly video address, Zelenskiy hailed Brussels’ support for Ukraine’s European Union bid as a “historic achievement”.
• The Russian president, Vladimir Putin, said Moscow had “nothing against” Ukraine’s possible membership of the European Union. He said on Friday after the European Commission recommended granting Kyiv candidate status of the 27-member bloc: “It’s their sovereign decision to join economic unions or not … It’s their business, the business of the Ukrainian people.”
• The German chancellor, Olaf Scholz, said it was “absolutely necessary” for leaders to speak directly with Putin in attempts to end the war. “I will continue to do so, as the French president will also,” Scholz told German news agency DPA on Friday.
• Four civilians died and six were wounded on Friday in Russian bombing in the Donetsk region of the Donbas, governor Pavlo Kyrylenko said on Telegram.
• Dozens of Ukrainian civilians performed military exercises on Friday in fortified positions left by Russian troops in Bucha, a town synonymous with war crimes blamed on Moscow’s forces.
• Lithuania has told the Russian region of Kaliningrad it will block the import and export of a large number of goods by rail because of western sanctions, the regional governor said on Friday. The region is home to the Russian Baltic fleet and a deployment location for nuclear-capable Iskander missiles.
• Ukraine received a $733m loan from Canada. Ukraine’s finance ministry said on Friday the funds would be “directed to the state budget to finance priority expenditures – in particular, to ensure priority social and humanitarian expenditures”.
• The Biden administration’s plan to sell four large, armable drones to Ukraine has been paused over the fear its sophisticated surveillance equipment might fall into enemy hands, Reuters reported, citing two people familiar with the matter.
• Russian media has supposedly shown images of two US citizens captured in Ukraine. On Friday, the Izvestia newspaper showed footage of what it said was an interview with Andy Huynh, 27. The Russian channel RT also posted a photo of a man it identified as Alexander Drueke, 39. Drueke’s mother, Lois Drueke, told the Guardian she believed the clip was authentic and it gave her “great hope”.
• US Republican senators on Friday asked the TikTok chief executive, Shou Zi Chew, about reports the social media site had allowed Russian state-approved media content but barred other videos. TikTok said it was looking forward to continuing to engage with members on these issues and answering their questions.
• A group of international investigators and experts have visited war-torn areas near Kyiv, including a burnt-out school, as part of Ukraine’s ongoing investigation into alleged war crimes.