LIVE - Updated at 06:39
The war in Ukraine could last for "decades" with long periods of fighting interspersed by truces, one of Russian president Vladimir Putin's most senior aides has predicted.
"This conflict will last a very long time, most likely decades," former Russian president Dmitry Medvedev said during a visit to Vietnam.
"As long as there is such a power in place, there will be, say, three years of truce, two years of conflict, and everything will be repeated," the deputy chairman of Putin's powerful security council continued, while reiterating Moscow's claim that Ukraine is a Nazi state.
On the frontline, Russia's Wagner mercenaries have started handing over positions in Bakhmut to the regular Russian military, five days after claiming to have completed the capture of the devastated eastern Ukrainian city.
But Ukrainian deputy defence minister Hanna Maliar said Wagner has only handed over positions on the city's outskirts and "inside the city itself Wagner fighters remain".
Wagner chief Yevgeny Prigozhin has said he is ready to return his forces to Bakhmut if the regular army is struggling.
One of Russian president Vladimir Putin's top aides has said the war in Ukraine could last for decades, with long periods of fighting interspersed by truces, a state news agency reported today.
"This conflict will last a very long time, most likely decades," former Russian president Dmitry Medvedev said.
"As long as there is such a power in place, there will be, say, three years of truce, two years of conflict, and everything will be repeated," he continued, reiterating Moscow's claim that Ukraine is a Nazi state.
The remarks by the deputy chairman of Putin's powerful security council were made during a visit to Vietnam, reported RIA news agency. He had described the Ukrainian authorities as an "infection".
Volodymyr Zelensky announced the return of over a hundred Ukrainian soldiers, initially considered missing in the battlefield, who fought in the grinding battle of Bakhmut last night.
"Today we have another positive result from our team working on exchanges. We have returned 106 more of our warriors from Russian captivity - they fought in the Bakhmut sector," Mr Zelensky said in his nightly address.
He added: "It is very important that there was no information about many of these 106 people at all - they were considered missing. But we found them. We brought them back home. 8 officers, 98 soldiers and sergeants."
Russia will need to launch a pre-emptive strike if the West gives nuclear weapons to Ukraine, one of the Russian president's closest aides has said.
"There are irreversible laws of war. If it comes to nuclear weapons, there will have to be a pre-emptive strike," former Russian prime minister Dmitry Medvedev said, according to Russian state media.
At the start of this week, an unknown number of paramilitaries entered the Russian region of Belgorod from Ukraine.
The details are both unclear and contested, but what appears to have happened is essentially this: they took over a border post, attacked a few villages on the Russian side of the border north of Ukraine's second city, Kharkiv, and advanced several dozen kilometres further into Russia before being beaten back by Russian troops.
Russia claims they killed 70, but there is no corroboration.
Ukraine says it was a couple of Russian volunteer groups opposed to President Putin, operating independently of the Kyiv government; Russia says it was Ukrainian saboteurs and terrorists operating with the full knowledge and support of Kyiv. But whoever was behind this raid is a secondary detail to the fact that it happened.
Read the full story here:
As the Ukraine war spills into Russia, a new front is set to explode | Mary Dejevsky
Ukraine is celebrating the return of more than 100 soldiers from captivity.
"Today we have another positive result from our team working on exchanges," Ukraine's president Volodymyr Zelensky said on Twitter.
"We have returned 106 more of warriors from captivity - they fought in the Bakhmut sector. It is very important that there was no information about many of these 106 people at all - they were considered missing. But we found them.
"We brought them back home. 8 officers, 98 soldiers and sergeants... I thank everyone who gave this result."
Russia's Wagner private army started handing over its positions in Bakhmut to regular Russian troops yesterday, five days after announcing complete capture of the devastated eastern Ukrainian city following the longest and bloodiest battle of the war.
"From today at five in the morning, May 25 until June 1, most of the (Wagner) units will rebase to camps in the rear," Wagner chief Yevgeny Prighozin said in a video. The mercenary group's leader was wearing battle gear and standing beside a war-damaged residential block.
However, Ukrainian deputy defence minister Hanna Maliar said Wagner has only handed over positions on the city's outskirts but "inside the city itself Wagner fighters remain".
Prigozhin has said his fighting unit would be ready to return to the city if needed.
Military authorities in Kyiv warned of an increased danger of Russian missile strikes in the early hours today, adding that the anti-aircraft defences were working.
"Increased missile danger! Air defences are working in the region," the Kyiv regional military administration said in a message on Telegram.
Russia has targeted all of Ukraine and especially Kyiv in the recent months with early morning combined strikes of drones, cruise and ballistic missiles in a bid to overwhelm Ukraine's air defences.
However, Kyiv says it has knocked out most of the Russian missiles headed towards Ukrainian cities with a high rate of success since April.
No details of possible damage were immediately available.
During a surprise commencement address to graduates of Johns Hopkins University on Thursday morning, Ukrainian president Volodymyr Zelensky told them to take advantage of the time and resources they have to pursue their passions and uphold the democratic values at stake in his country's war against Russia.
He spoke via livestream from Ukraine, where the ongoing conflict has impacted the futures of countless young Ukrainians, robbing them of opportunities and loved ones, Mr Zelensky said.
He told Hopkins graduates to make the most of every moment.
"Time is the most valuable resource on the planet," he said. "Some people realize this sooner, and these are the lucky ones.
Others realize it too late, when they lose someone or something."
He also thanked US leaders for their support since the Russian invasion, including significant investments in humanitarian and military aid.
The leaders of Azerbaijan and Armenia on Thursday both spoke of progress towards ending their decades-old conflict over the territory of Nagorno-Karabakh, even as they argued openly in front of Russian president Vladimir Putin.
Nagorno-Karabakh, an Armenian-populated enclave inside Azerbaijan, has been a source of conflict between the two Caucasus neighbours since the years leading up to the collapse of the Soviet Union in 1991, and between ethnic Armenians and Turkic Azeris for well over a century.
In 2020, Azerbaijan seized control of areas that had been controlled by ethnic Armenians in and around the mountain enclave, and since then it has periodically restricted access to the only access road linking Nagorno-Karabakh with Armenia, on which the enclave relies for financial and military support.
At a meeting in Moscow, Armenian prime minister Nikol Pashinyan accused Azerbaijan of causing a humanitarian crisis by blocking the only land route from Armenia to Nagorno-Karabakh.
He called it a "direct violation" of a 2020 ceasefire that ended the six-week war between the two countries, and called for an international mission to be sent to evaluate the situation.
A US senator on Thursday said he hopes Serbia would adopt Western sanctions against Russia over its invasion of Ukraine, telling the Balkan country that "there is no future" in an alliance with Moscow.
"Russia's invasion has been an absolute disaster and my belief is that Russia is ultimately going to lose this conflict," Senator Chris Murphy told reporters in the Serbian capital Belgrade. Serbia is the only country in Europe that has not imposed any sanctions on Russia.
"The future for Serbia is with the European Union and with the United States not with Russia," Mr Murphy said. "There is no future with Russia. They (Russia) are going to be devastated, a permanent pariah internationally after this invasion."
Though Serbia is formally seeking EU membership and has condemned the invasion at the United Nations, Belgrade has maintained its historically friendly relations with Moscow.
Pål Jonson, Sweden's minister for defence, has been in talks with Ukraine counterparts over what support the Scandinavian country can bring.
Mr Jonson was joined by his party colleague Carl-Oskar Bohlin for the visit on Thursday.
The minister for defence tweeted: "Impressed by the performance of the Ukrainian armed forces and the resilience of the Ukrainian people."
Ukraine secured the release of 106 captured soldiers in a prisoner exchange with Russia on Thursday, president Volodymyr Zelensky's chief of staff said.
The soldiers, including eight officers, were captured fighting in the devastated eastern city of Bakhmut that Russia says it has captured, but where Kyiv's forces say they still have a small foothold.
"Every one of them is a hero of our state. Many of the ones we are returning from captivity were considered missing. The relatives of these people have gone through a difficult time," the senior official, Andriy Yermak, said.
Tatiana Moskalkova, Russia's human rights ombudsman, confirmed Russia's Wagner private military unit took part in an exchange of fighters on Thursday, but gave no further details.
Wagner played a key role in Russia's months-long onslaught on the city of Bakhmut where both sides likened the ferocious fighting to a "meatgrinder".
Russia launched a full-scale invasion of its neighbour in February 2022. Ukrainian military intelligence says that 2,430 Ukrainians have been freed in prisoner swaps, including 139 civilians.
Ukraine leaders said on Thursday they would consider opening more embassies in Africa and hold a summit between the country and continent.
The Guardian reported Dmytro Kuleba, Ukraine's foreign minister, said: "We have recently adopted our first African strategy and intensified our political dialogue with many countries on the continent.
"This year, we are going to establish new embassies in different parts of the continent and plan to hold the first Ukraine-Africa Summit."
Sweden's defense minister says the Nordic country is considering whether to let Ukrainian pilots test its JAS 39 Gripen fighter jets.
So far, Sweden has ruled out sending any Gripen fighters to Ukraine, saying it needs them for its own territorial defense.
But defence minister Pål Jonsson told Swedish broadcaster TV4 that Sweden was looking with a "positive spirit" on a Ukrainian request to allow its pilots to try out the Swedish plane.
"That could, for example, mean test flights, using simulators, learning more about the extensive ground system that is part of the Gripen system," he said.
Ukraine has long asked for Western fighter jets to help it resist the full-scale Russian invasion, now in its second year.
Initially reluctant, the U.S. and other NATO countries recently agreed to allow Ukrainian pilots to receive training to fly F-16 fighters, though none has yet committed to hand over any planes.
MPs have voted in favour of recognising a famine that engulfed Ukraine in the 1930s as a genocide against the country's people.
The House of Commons unanimously supported a motion to recognise the Holodomor as a genocide.
The famine is widely agreed to be man-made, and occurred between 1932 and 1933, killing millions of Ukrainians.
A growing number of countries have recognised the Holodomor as a genocide, as they consider it a purposeful attempt by the Soviet government to kill Ukrainians.
The backbench motion, tabled by Conservative MP Pauline Latham (Mid Derbyshire), is non-binding.
But Ms Latham urged MPs to support it as a means of sending a message to Russian President Vladimir Putin about his invasion of Ukraine.
Sweden may allow a few Ukrainian fighter jet pilots to test fly the Nordic country's Gripen aircraft, Stockholm's defence minister has said.
But in his comments to broadcaster TV4 on Thursday, Pal Jonson repeated earlier insistences that Sweden has no plans to send any of its Gripen to Ukraine, as all six divisions are required for the defence of Sweden's territory.
"This concerns the Ukrainians putting in inquiries about various kinds of aviation systems - it can be Tornados, F-16s or Gripens - so that they can test the kinds of platforms and systems that we and other countries operate," Jonson said.
"We are now looking at the possibility that the Ukrainians can test the Gripen."
Such an initiative could involve test flights, trying simulators and learning about the fighter jet's ground support system that, he said, adding: "Some decisions remain, both on the Ukrainian and the Swedish side."
Russian prosecutors have asked a court to recognise crimes committed by Nazi Germany in the Moscow region as genocide and claim to believe that around 6.4 trillion roubles (£66.8 trillion) in damage was caused.
It was unclear whether the move was a prelude to a new financial compensation claim from Russia to modern Germany, with which relations have soured badly over Moscow's war in Ukraine.
But the statement, which cited the need to defend Russia's national interests while restoring historical justice, appeared part of a wider effort by Russia to gird its citizens for what it says is an existential war with the West, which some Russian officials have likened to the one fought by the Soviet Union against the Nazis.
The prosecutors asked a Moscow regional court "to recognise as war crimes and crimes against humanity, and as genocide against the Soviet people, the established and newly revealed crimes committed by the German fascist invaders" in the Moscow region between October 1941 and January 1942.
More than 26,000 people were killed in the region during that time, they said in a statement, with Soviet citizens subjected to torture, robbery, forced labour and expulsions. It was not clear how soon the court would rule on the request.
Russia has summoned the ambassadors of Germany, Sweden and Denmark in protest over what it said was the "complete lack of results" in an investigation into who blew up the Nord Stream gas pipelines.
The underwater blasts last September occurred in the economic zones of Sweden and Denmark, and the two countries are investigating the explosions - which they say were deliberate - alongside Germany.
In a new statement, Russia's foreign ministry claimed: "It has been noted that these countries are not interested in establishing the true circumstances of this sabotage. On the contrary, they are delaying their efforts and trying to conceal the tracks and the true perpetrators of the crime behind which we believe are well-known countries."
"It is no coincidence that 'leaked' improbable versions [of what happened] are dumped in the media to try to muddy the waters," the ministry said.
The Danish foreign ministry confirmed that its ambassador had been summoned, and said authorities in Denmark, Germany, and Sweden were continuing their investigations.
"Denmark has been providing ongoing updates to Russia regarding the investigation's progress and responding to their inquiries. We will continue to do so," the ministry told Reuters.
Belarus president Alexander Lukashenko has claimed that the relocation of some of Russia's tactical nuclear weapons to Belarus has already started, state news agency Tass reports.
Russia signed a deal with its close ally Belarus earlier on Thursday about the storage of the warheads at a special facility, which it claims should be completed in just over a month's time.
The European Commission has repeated calls for China to play a constructive role in establishing peace in Ukraine, after a top EU diplomat met Li Hui, China's special representative for Eurasian Affairs and former ambassador to Russia.
"The EU expects China, as a permanent member of the UN Security Council, to play a constructive role ... and to recall the necessity to respect the principles of sovereignty, independence and territorial integrity ... by unconditionally withdrawing all forces and military equipment from the entire territory of Ukraine within its internationally recognised borders," the EU said in a statement.
Last week, Li Hui visited Ukraine and met president Volodymyr Zelensky in a European tour that Beijing billed as its effort to promote peace talks and a political settlement. He is set to visit Russia on Friday.
Cyprus said on Thursday it was committed to upholding European Union sanctions on Russia over its invasion of Ukraine and urged the bloc to support sectors, such as shipping, that have felt the impact of EU decision.
"Right from the start, Cyprus has been implementing all the sanctions related to the Russian invasion to Ukraine", President Nikos Christodoulides said after meeting German Chancellor Olaf Scholz in Berlin. "We're on the right side of history and we will continue in the same direction."
"Where there is a cost for the European industries due to the decisions that we take - the right decisions that we take - the European Union should intervene to support those sectors."
Russia and Belarus signed a deal on Thursday formalizing the procedure for deploying Russian nuclear weapons on Belarusian territory. Control of the weapons will remain with Moscow.
The move formalized the deal agreed on earlier by Russian President Vladimir Putin and Belarusian President Alexander Lukashenko. Putin previously announced in March that his country planned to deploy tactical, comparatively short-range and small-yield nuclear weapons in Belarus. The inking of the deal comes as Russia braces for Ukraine's much-anticipated counteroffensive.
Both Russian and Belarusian officials framed the step as driven by hostility from the West.
Russia signs deal to deploy tactical nuclear weapons in Belarus
Russia said on Thursday it would expel five Swedish diplomats in what it said was a retaliatory measure for Sweden's "confrontational course" in relations with Russia.
The Russian Foreign Ministry said it was responding to the expulsion of five of its diplomatic staff from Sweden last month, which it called an "openly hostile step".
Relations between the two countries have worsened since Sweden last year announced its intention to join NATO following Russia's invasion of Ukraine. The Russian statement said ties had "reached an unprecedented low".
Russia's Foreign Ministry said on Thursday it had summoned the ambassadors of Germany, Sweden and Denmark to protest over what it said was the "complete lack of results" in an investigation to identify who blew up the Nord Stream gas pipelines last year.
Several unexplained underwater explosions ruptured the Nord Stream 1 and newly-built Nord Stream 2 pipelines that link Russia and Germany across the Baltic Sea in September 2022.
The blasts occurred in the economic zones of Sweden and Denmark and both countries say the explosions were deliberate, but have yet to determine who was responsible. The two countries and Germany are investigating the incident.
Russia's Foreign Ministry in a statement accused all three of deliberately dragging their feet and of trying to conceal who was behind the blasts.
It said it was unhappy about what it called the opaque nature of the investigation and its refusal to engage with Russia.
"It has been noted that these countries are not interested in establishing the true circumstances of this sabotage. On the contrary, they are delaying their efforts and trying to conceal the tracks and the true perpetrators of the crime behind which we believe are well-known countries," it said.
"It is no coincidence that 'leaked' improbable versions (of what happened) are dumped in the media to try to muddy the waters."
The United States and the North Atlantic Treaty Organisation have called the incident "an act of sabotage." Moscow has blamed the West. Neither side has provided evidence.
The ministry said Moscow would keep trying to ensure that Germany, Denmark and Sweden conducted what it called an objective investigation with Russia participating too.
Watch live as US secretary of defense Lloyd Austin delivers opening remarks at a meeting of the Ukraine Defense Contact Group.
Live: Pentagon chief Lloyd Austin speaks at Ukraine Defense Contact Group meeting
Ukraine will not be able to join Nato as long as Russia's invasion continues, the head of the alliance has said.
"To become a member in the midst of a war is not on the agenda," Jens Stoltenberg said. "The issue is what happens when the war ends."
Last September, Ukrainian president Volodymyr Zelensky announced a bid for fast-track membership of Nato after Russia's president Vladimir Putin proclaimed four partially-occupied regions of Ukraine as annexed Russian land as part of Moscow's invasion. Since then, there have been plenty of platitudes from Nato members about how Ukraine belongs in the alliance, but little concrete action, with some Western allies of Kyiv wary of moves that could push Nato towards an active war with Russia.
At an event organised by think tank German Marshall Fund of The United States in Brussels, Mr Stoltenberg acknowledged there were differences among the alliance over how to address Kyiv's membership ambitions.
Nato chief says Ukraine should not join alliance until Russia's invasion is over
Russia has replaced its Wagner private military units with regular soldiers in the outskirts of Bakhmut but the group's fighters remain inside the devastated city, Deputy Defence Minister Hanna Maliar said on Thursday.
Her comments appeared at least partially to confirm an announcement by Wagner founder Yevgeny Prigozhin that his group had started withdrawing its forces from Bakhmut in east Ukraine and handing over its positions to regular Russian troops.
Russia said on Thursday it would shut Sweden's consulate in St Petersburg and its own mission in Sweden's second-biggest city Gothenburg, and expelled five Swedish diplomats in a tit-for-tat move after Stockholm expelled five Russians last month.
Stockholm said last month it had expelled the diplomats over espionage concerns. The Russian Foreign Ministry called the expulsions an "openly hostile step".
It said it had withdrawn its consent for the Swedish consulate in St Petersburg from September.
Swedish Foreign Minister Tobias Billstrom said in a statement the news was "very regrettable" and "further confirmation of the negative political development in Russia and the country's international isolation".
"Russia has chosen to expel Swedish diplomats who acted within the framework of the Vienna Convention and conducted customary diplomatic activities in Russia. We also deeply regret the Russian announcement about the Consulate General in St Petersburg," he said.
Relations between the two countries have worsened since Sweden last year announced its intention to join NATO following Russia's invasion of Ukraine. The Russian statement said ties had "reached an unprecedented low".
Russia and Belarus signed a deal on Thursday to formalise the deployment of Russian tactical nuclear missiles on Belarusian territory, a step Moscow said was driven by rising tensions with the West.
"In the context of an extremely sharp escalation of threats on the western borders of Russia and Belarus, a decision was made to take countermeasures in the military-nuclear sphere," TASS news agency quoted Russian Defence Minister Sergei Shoigu as saying.
The deployment of the missiles was first announced by President Vladimir Putin in March. Since invading Ukraine last year, Putin has said repeatedly that Russia would be ready to use nuclear weapons if needed to defend its "territorial integrity".
NATO said at the time it did not see any need to adjust its own nuclear posture, though it said Putin's nuclear rhetoric was "dangerous and irresponsible".
Ukraine said Russia's ally Belarus had been "taken hostage" by Moscow.
Moscow will retain control over the weapons and any decisions on their use, Shoigu said.
TASS quoted him as saying that Iskander-M missiles, which can carry conventional or nuclear warheads, had been handed to the Belarusian armed forces, and some Su-25 aircraft had been converted for the possible use of nuclear weapons.
"Belarusian servicemen have received the necessary training in Russian training centres," Shoigu was quoted as saying.
He added that the agreements signed with his Belarusian counterpart covered the procedure for establishing a "special storage facility for nuclear weapons on Belarusian territory."
Tactical nuclear weapons refer to lower-yield weapons designed for battlefield use, as opposed to strategic ones capable of wiping out entire cities. Russia has not disclosed how many tactical nuclear weapons it has.
Russia's Wagner mercenary group has started withdrawing its forces from the Ukrainian city of Bakhmut and transferring its positions there to regular Russian troops, its founder Yevgeny Prigozhin said in a video published on Thursday.
"We are withdrawing the units from Bakhmut. From today at five in the morning, May 25 until June 1, most of the units will rebase to camps in the rear. We are handing our positions to the military," he said.
The video was posted on Telegram by his press service, and showed Prigozhin dressed in battle gear and standing beside a war-damaged residential block.
Prigozhin announced the capture of Bakhmut on Saturday after the longest and bloodiest battle of the war.
In the latest video Prigozhin, who has repeatedly voiced public criticism of senior Russian defence officials, said his forces would be ready to return to Bakhmut if the regular army was unable to manage the situation.