STORY: Russian state television on Thursday broadcast footage of two Brits and a Moroccan who were captured while fighting for Ukraine being sentenced to death by a court in the self-proclaimed Donetsk People's Republic (DPR), one of Russia's proxies in eastern Ukraine.
Video released by the DPR Supreme Court on Wednesday showed Brits Aiden Aslin and Shaun Pinner, and Moroccan Brahim Saadoun pleading guilty.
Their lawyer said they will appeal the decision.
British Foreign Secretary Liz Truss on Thursday tweeted her condemnation of the sentence.
She wrote, "they are prisoners of war. This is a sham judgement with absolutely no legitimacy."
Aslin and Pinner were captured in April while fighting on the Ukrainian side.
After they were taken prisoner, Russian TV showed a clip of Aslin appealing to British Prime Minister Boris Johnson and Ukrainian President Volodymyr Zelenskiy to trade the captured Brits for Viktor Medvedchuk, an ally of Russian President Vladimir Putin detained by Ukrainian authorities.
"If Boris Johnson really does care like he says he does about British citizens, then he would help pressure Zelenskiy to do the right thing and return Viktor to his family, and return us to our families."
"This is the most egregious breach of international law, and these individuals need to be released immediately and returned to their families."
In an appearance on the BBC, British Conservative Party lawmaker Robert Jenrick called the sentence the result of a "Soviet-era show trial."
"You cannot treat British citizens in this manner and get away with it."
The sentence comes after a Ukrainian court last month sentenced two captured Russian soldiers to eleven-and-a-half years in jail after they pleaded guilty to firing artillery at civilian targets. Another Russian soldier was sentenced to life in prison after pleading guilting to shooting dead an unarmed civilian.
Both sides have taken prisoners since Russian troops invaded Ukraine at the end of February in what Moscow calls a "special military operation" and Ukraine and Western nations condemned as an unprovoked war of aggression.