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The family of British man Shaun Pinner, who has been sentenced to death by a court by Russian proxy authorities in Donbas, have spoken of their devastation at the news and requested he is exchanged or released.
Mr Pinner was among two Britons and a Moroccan who were captured and convicted of "mercenary activities" on Thursday by a court in the self-proclaimed Donetsk People's Republic (DPR), whose separatist leaders are backed by Moscow.
"Firstly, our whole family is devastated and saddened at the outcome of the illegal show trial by the so-called Donetsk People’s Republic," the family said.
"Shaun should be accorded all the rights of a prisoner of war according to the Geneva Conventions and including full independent legal representation. We sincerely hope that all parties will co-operate urgently to ensure the safe release or exchange of Shaun."
Ukraine is doing everything possible to save three foreign nationals who were sentenced to death by proxy, a member of the country's parliamentary security and defence committee said on Saturday.
"Both the Defence Ministry and the Main Directorate of Intelligence, which deals with the exchange of prisoners, are taking all necessary measures to ensure these citizens of foreign states ... are saved," said Member of Parliament Fedir Venislavskyi national television.
He did not give further details.
Deputy Prime Minister Iryna Vereshchuk said she believed the separatist authorities would ultimately act rationally, "for they are well aware of the irreparable implications for them and for the Russians if they take any wrong steps against these three of our soldiers."
"Something tells me that, eventually, one way or another, sooner or later, these three servicemen will be exchanged [or otherwise get home]," she said in an online post on Saturday.
Ukraine’s ambassador to the UK, Vadym Prystaiko, suggested on Friday that negotiations for a possible prisoner swap with Moscow were under way, as it emerged Defence Secretary Ben Wallace had made a surprise visit to Kyiv for talks with Ukrainian President Volodymyr Zelenskyy.
Later that day, Ms Truss said she had spoken with Ukrainian foreign minister Dmytro Kuleba “to discuss efforts to secure the release of prisoners of war held by Russian proxies”.
Britain has condemned the sentencing of the fighters as an "egregious breach" of the Geneva Conventions, under which prisoners of war are entitled to combatant immunity and should not be prosecuted for participation in hostilities.
Ukraine, which has dismissed the Donetsk court's ruling as having no authority, says the fighters had signed contracts with the Ukrainian armed forces.
As a result, "the status of prisoners of war under international law fully applies to them. We will take all measures to save them," Mr Venislavskyi said.
