Foreign Secretary Liz Truss vows to do everything possible to secure release of Brit prisoners Aiden Aslin, from Newark, and Shaun Pinner, from Bedfordshire, who face the death penalty in Donetsk

Foreign Secretary Liz Truss has vowed to do everything possible to secure the release of two Brit prisoners of war sentenced to death in Ukraine.

A court not recognised by international law in the breakaway self-proclaimed Donetsk People’s Republic has sentenced Newark's Aiden Aslin, 28, and Bedfordshire's Shaun Pinner, 48, to death.

They have under a month to appeal.

Both men were captured in April in Mariupol fighting with Ukraine's 36th Marine Brigade, having been ordered to surrender after running out of food and ammunition.

They were serving members of the Ukrainian armed forces long before hostilities began, rather than the foreign mercenaries they are painted as being for political gain.

Liz Truss did not rule out negotiating directly with Donetsk People’s Republic, but said the best route to their release was dealing with Kyiv and she has been speaking directly with her Ukrainian counterpart Dmytro Kuleba.

“I can’t go into my discussions with the Ukrainians but I can assure the families we’re working flat out on this,” she said.

It is argued the men, along with Moroccan national Saaudun Brahim, 21, who was a Kyiv resident and has also been sentenced to the death penalty, should be treated as prisoners of war under the Geneva Convention.

Comments by Denis Pushilin, the head of the unrecognised Donetsk People's Republic, dented hopes of a prisoner swap between Ukraine and Russia.

"First of all, I must be guided by the court decision that has been made," Mr Pushilin said, according to Russian media.

"By the nature of those articles, those offences that they committed, I see no grounds or prerequisites for me to pardon them.

"They came to Ukraine to kill civilians for money. That's why I don't see any conditions for any mitigation or modification of the sentence."

He added the court had issued a perfectly fair punishment to the three fighters.