Britain has again condemned the death sentences handed to two Britons by Russia-backed separatists in Ukraine’s eastern region of Donetsk, while a United Nations spokesman and the German government have also issued strong reactions to the sentence.

Britons Aiden Aslin and Shaun Pinner along with Moroccan Saaudun Brahim were sentenced to death on June 9 for “mercenary activities.” All three say they were serving in the Ukrainian military when they were captured by pro-Russian separatists while fighting Russian forces.

Aslin’s family said he and Pinner were living in Ukraine when the war broke out in February and “as members of Ukrainian armed forces, should be treated with respect just like any other prisoners of war.”

British Foreign Minister Liz Truss on June 10 called the sentencing of Aslin and Pinner an “egregious breach” of the Geneva Conventions.

Britain’s priority is to work with the Ukrainian government to secure the soldiers’ release as quickly as possible, Prime Minister Boris Johnson’s spokesman said. Johnson’s office said he was “appalled” by the death sentences.

Ukrainian Foreign Minister Dmytro Kuleba condemned what he called a “sham trial against prisoners of war,” and Ukraine’s Prosecutor-General’s Office said it was probing the case.

The United Nations warned that unfair trials of prisoners of war amounted to war crimes.

A UN official, speaking in Geneva on June 10, expressed concern about the sentences, saying that trials under circumstances such as the one the men faced were tantamount to war crimes under the Geneva Conventions.

“According to the chief command of Ukraine, all the men were part of the Ukrainian armed forces — and if that is the case, they should not be considered as mercenaries,” he told reporters.

Germany blasted Russia over the “shocking” death sentences, saying they show “once more Russia’s complete disregard for international humanitarian law.”

Germany’s Foreign Ministry pointed out on Twitter that combatants are entitled to protections under the Geneva Conventions.

According to Russian Foreign Minister Sergei Lavrov, the three men committed crimes on the territory of what the separatists’ leaders call the Donetsk People’s Republic (DPR).

Russia’s Foreign Ministry said Britain should appeal to the self-proclaimed DPR authorities about the soldiers. Britain does not recognize the DPR.

Among United Nations member states, only Russia recognizes the entire Ukrainian province of Donetsk as the Donetsk People’s Republic. The territory is internationally recognized as part of Ukraine.