Australia has vowed it will take the “strongest action possible” if Russia has harmed one of its nationals captured fighting for Ukraine, after reports emerged the prisoner of war may have been killed.

The government is considering diplomatic retaliation if reports that Melbourne man Oscar Jenkins has been killed in Ukraine by Russian forces are confirmed.

There are fears an Australian man captured by Russian forces while fighting for Ukraine has been executed. Oscar Jenkins, a 32-year-old teacher from Melbourne, was reportedly captured in the Donbas region.

The federal government is making urgent enquiries following reports Australian prisoner of war Oscar Jenkins has been killed by Russian forces in Ukraine.