Russia and Ukraine exchanged 35 prisoners on each side in a long-awaited swap that could help thaw relations between the two countries.

A Russian aircraft carrying freed Russian prisoners from Kiev landed in Moscow while a Ukrainian plane with released Ukrainian prisoners aboard touched down in Kiev on Saturday.

The Ukrainian prisoners included Oleg Sentsov, a Ukranian filmmaker who was imprisoned in Russia after being convicted of plotting terrorist acts, Ukrainian journalist Roman Suschenko and 24 sailors who were seized in the Kerch Strait by Russia in November last year, Mr Sentsov's lawyer, Mark Feygin, said.

Marie Struthers, Amnesty International’s director for eastern Europe and central Asia, said: “Oleg Sentsov and many others jailed following Russia’s occupation and illegal annexation of Crimea are simply victims of politically-motivated prosecution and they should never have been imprisoned in the first place.

"While it is a relief that they are now free, it is a travesty to see them being used as human bargaining chips in political deals."

Ukrainians react after Russia seizes ships Show all 13 1 /13 Ukrainians react after Russia seizes ships Ukrainians react after Russia seizes ships A protester throws a smoke grenade during a rally in front of the Russian embassy in Kiev on Sunday 25 November EPA Ukrainians react after Russia seizes ships The Ukrainian National Guard is on the scene of protests at the Russian embassy in Kiev on Sunday 25 November Reuters Ukrainians react after Russia seizes ships Members of the right-wing paramilitary Azov National Corps light flares during a rally in front of the Verkhovna Rada in Kiev on Monday 26 November AP Ukrainians react after Russia seizes ships Ukrainian police guard the Russian embassy building in Kiev on Sunday 25 November EPA Ukrainians react after Russia seizes ships A protester throws a smoke grenade during a rally in front of the Russian embassy in Kiev on Sunday 25 November AP Ukrainians react after Russia seizes ships A protester piles up tires to burn outside of the Russian embassy in Kiev on Sunday 25 November Reuters Ukrainians react after Russia seizes ships Far-right activists rally outside the Verkhovna Rada (Ukrainian parliament) building in Kiev on Monday 26 November AFP/Getty Ukrainians react after Russia seizes ships Ukrainian Nationalists burn flares and smoke grenades as they rally in front of the Verkhovna Rada (Ukrainian parliament) building in Kiev on Monday 26 November EPA Ukrainians react after Russia seizes ships Paper boats outside of the Russian embassy in Kiev on Sunday 25 November AFP/Getty Ukrainians react after Russia seizes ships Far-right activists rally outside the Verkhovna Rada (Ukrainian parliament) building in Kiev on Monday 26 November Reuters Ukrainians react after Russia seizes ships A protester places a paper boat outside of the Russian embassy in Kiev on Sunday 25 November Reuters Ukrainians react after Russia seizes ships Far-right activists march on the Verkhovna Rada (Ukrainian parliament) building in Kiev on Monday 26 November AFP/Getty Ukrainians react after Russia seizes ships Ukrainian Nationalists burn flares as they rally in front of the Verkhovna Rada (Ukrainian parliament) building in Kiev on Monday 26 November AFP/Getty

She added: “The conflict in eastern Ukraine opened a new and tragic chapter for human rights in the country and beyond. Following his arrest, illegal transfer to Russia and deeply flawed trial by a military court, Oleg Sentsov spent more than six years behind bars.

“The Russian authorities derisively refused to recognise his Ukrainian citizenship and transported him 3,000km away from his family and native Crimea to the frost-bitten penal colony at Labytnangi in the far north of Russia.

“No-one should be prosecuted and imprisoned solely for political reasons; we demand justice for all remaining prisoners subjected to these politically-motivated trials, those who had been imprisoned solely for exercising their human rights, should be immediately and unconditionally release.”

Volodymyr Zelenskiy, Ukraine's president, hugged and shook hands with the freed Ukrainians while Russia's Rossiya 24 TV showed Russian prisoners disembarking the plane in Moscow.

Mr Zelenskiy told reporters at the Kiev airport the swap was part of his deal with Vladimir Putin, the Russian president.

He said all steps had to be taken "to finish this horrible war," referring to the five-year-old conflict with pro-Russian separatists in eastern Ukraine.

The swap was carried out on a "35-to-35" basis, Interfax news agency quoted Russia's human rights commissioner, Tatyana Moskalkova, as saying.

"Ukraine has handed out 35 people to Russia, we handed out the same number to Ukraine," she said.

"We view the agreed mutual release of persons held in Russia and Ukraine as a positive signal that should be followed by other important steps to break the impasse in the current situation in Russia-Ukraine relations," the Russian foreign ministry said in a statement.

Donald Trump, the US president, congratulated Russia and Ukraine on the swap, saying in a tweet the move was "very good news, perhaps a first giant step to peace".

It was not clear who was on board the Russian plane, aside from Kirill Vyshinsky, head of the Russian state news agency RIA-Novosti’s Ukraine branch, who had been jailed since 2018 on treason charges.

His presence was confirmed by Dmitry Kiselev, head of the Rossiya Segodnya media group that includes the agency.

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The exchange could be a significant step towards easing relations between the two countries and raising the likelihood of resolving the conflict in Ukraine’s east, where fighting between troops and Russia-backed separatists has killed more than 13,000 people since 2014.

Ukraine still wants the Crimea region back, which Russia annexed in 2014, and Russian-backed separatists continue to control a swath of eastern Ukraine.