Australia has vowed to take the “strongest possible action” if it is confirmed that Russian forces have executed one of its citizens captured in Ukraine.

Ministers said they were “seeking urgent clarification” from Moscow about the condition of Oscar Jenkins after reports of his death circulated earlier this week.

The 32-year-old, from Melbourne, was serving with Ukrainian forces when he was captured by Russian troops last year.

A video emerged in December which showed a visibly shaken Mr Jenkins with his hands bound being interrogated by Russian troops. They were also seen hitting him on the head several times.

Mr Jenkins, who could be heard speaking Ukrainian and English, identifies himself in the footage as a teacher and says he “wants to help Ukraine” – as the interrogator asks him if “he wants to live”.

Australian media reported on Wednesday that Mr Jenkins had probably died in Russian captivity, citing Ukrainian military sources.