Two Britons and a Moroccan who were captured while fighting for Ukraine were sentenced to death today by a court in the self-proclaimed Donetsk People's Republic (DPR).
It is one of Russia's proxies in eastern Ukraine and their sentencing was reported by Russian news agencies.
The court found the three men - Britons Aiden Aslin and Shaun Pinner and Moroccan Brahim Saadoun - guilty of "mercenary activities and committing actions aimed at seizing power and overthrowing the constitutional order of the DPR," the Interfax news agency quoted a court official as saying.
The three men were captured while fighting for Ukraine against Russia and Russian-backed forces after Russia invaded on 24 February.
Their lawyer said they will appeal the decision.
The UK government said it is "deeply concerned" following the death sentences handed to Mr Aslin, 28 and Mr Pinner, 48, who were captured while fighting for Ukraine, Downing Street said.
Foreign Secretary Liz Truss said: "I utterly condemn the sentencing of Aiden Aslin and Shaun Pinner held by Russian proxies in eastern Ukraine.
"They are prisoners of war. This is a sham judgment with absolutely no legitimacy.
"My thoughts are with the families. We continue to do everything we can to support them."
I utterly condemn the sentencing of Aiden Aslin and Shaun Pinner held by Russian proxies in eastern Ukraine.— Liz Truss (@trussliz) June 9, 2022
They are prisoners of war. This is a sham judgment with absolutely no legitimacy.
My thoughts are with the families. We continue to do everything we can to support them.
Less than 24 hours before the verdict was handed down, Mr Pinner and Mr Saadoun had pleaded guilty to actions aimed at the violent seizure of power, a video shared from the court by the RIA Novosti news agency showed.
Mr Aslin appeared to have pleaded guilty to a lesser charge involving weapons and explosives.
"The evidence presented by the prosecution in this case allowed the court to pass a guilty verdict, not to mention the fact that all the defendants, without exception, pleaded guilty to all charges," judge Alexander Nikulin told reporters at the court.
"When passing the verdict, the court was guided not only by the prescribed norms and rules, but also by the most important, unshakable principle of justice.
"It was that which made it possible to take this complex and difficult decision to apply an exceptional measure of punishment in the form of the death penalty," he added.
Britain said it was deeply concerned.
"We've said continually that prisoners of war shouldn't be exploited for political purposes," British Prime Minister Boris Johnson's spokesman said.
Mr Johnson's spokesman said that under the Geneva Conventions, prisoners of war are entitled to combatant immunity, and they should not be prosecuted for participation in hostilities.
British citizens Mr Aslin and Mr Pinner were captured by the Russian-backed forces in Mariupol in April, during a bitter fight for control of the city.
Moroccan Mr Saadoun surrendered in March while fighting in a small town between Mariupol and the regional capital of Donetsk.
During the proceedings, the three men were held in a cage with black bars, guarded by soldiers with their faces covered and wearing arm-bands with the pro-war Z-logo, before being asked to stand while the verdict was read to them, a video from the courtroom published by the RIA Novosti news agency showed.
The hasty trial was held largely behind closed doors with information on proceedings handed to select state-owned Russian media agencies.
The Donetsk People's Republic is one of two breakaway Russian-backed entities in the Donbas region of eastern Ukraine, which Russia says it is fighting to "liberate" from Ukrainian forces.
Three days before launching its 24 February invasion of Ukraine, Russia recognised them as independent states in a move condemned by Ukraine and the West as illegal.
But they also said the only hope to turn the tide was more artillery to offset Russia's massive firepower.