Russia has violated the Geneva Conventions and thus international humanitarian law by imposing the death penalty on three prisoners of war. British Foreign Secretary Liz Truss said this on Friday. Two of the convicts are British.

A pro-Russian court in the Donetsk region of eastern Ukraine has sentenced British prisoners of war Aiden Aslin and Sean Penner being held in Mariupol. They were part of the defense of the Azovstal steel plant in Mariupol when they were captured.

Truss said: “The sentencing against them is an unprecedented violation of the Geneva Conventions.” She discussed the situation with her Ukrainian counterpart Dmytro Kuleba on Friday.

Truss did not elaborate on her statement. According to the Geneva Conventions, prisoners of war have the right to fair treatment and a fair trial with an independent judiciary.

A spokesman for British Prime Minister Boris Johnson said on Friday that the British were only talking to Ukraine about the release of prisoners of war.

Russia describes the UK’s response as hysterical

A spokesman for the Russian Foreign Ministry described the British response to the death sentences as “hysterical”.

“The UK often reacts hysterically to these kinds of things,” a statement on the ministry’s website read. “These guys are killers who have taken the wrong side.”

According to the Russians, the British should appeal to the leaders of the self-proclaimed People’s Republic in Donetsk. Russia is the only country in the world that has recognized the independence of the Donetsk and Luhansk republics.