However, Denis Pushilin, the head of the DPR, who is not internationally recognized, downplayed that prospect in comments reported by Russian media last week.
“First of all, I have to be guided by the court decision that has been made,” he said.
“Because of the nature of these articles, the crimes they committed, I see no reason or prerequisites for them to be forgiven.
“They came to Ukraine to kill civilians for money. That’s why I don’t see conditions for any mitigation or modification of the sentence.”
He added that the court “had imposed a perfectly fair punishment” on the three fighters.
The British were legal fighters who served in the Ukrainian armed forces and had full rights to the protection of prisoners of war under the Geneva Convention, British ministers had previously insisted.
Foreign Secretary Liz Truss said she had discussed the case with her Ukrainian counterpart, Dmytro Kulebo, earlier this month.
Mr Aslin, 28, is a former care worker in Newark and Mr Pinner, 48, is a former British soldier in the Royal Anglian Regiment. Both had moved to Ukraine in 2018 and signed military contracts with the Ukrainian army.
Brahim Saadoune’s family said he had enlisted as a soldier hired in the Ukrainian army in 2021.