Officials are investigating reports another Australian volunteer solider has been killed in Ukraine.

The solider was a combat medic with the nickname “Mozzie”.

WATCH THE VIDEO ABOVE: Australian combat medic feared killed fighting in Ukraine

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Online reports have spoken glowingly of his heroism on the battlefield.

“I just heard the news. RIP brother,” said one person posting online.

“Will drink to you next Anzac Day. Absolute warrior.”

He had previously served with the Australian Army before volunteering to fight in Ukraine.

The Department of Foreign Affairs and Trade is now making inquiries with local authorities.

An Australian soldier with the nickname ‘Mozzie’ is feared dead in Ukraine. Credit: 7NEWS

At least 14 Australians have now been killed fighting in the Ukraine-Russia conflict.

Samuel Michael Pedrazzini, 26, from Lismore in NSW’s Northern Rivers region, was killed in June.

The latest reported death comes after Melbourne school teacher Oscar Jenkins spoke for the first time since he was jailed by Russia.

Jenkins, who was captured while serving as a soldier for Ukraine, said he headed to the conflict zone having wanted to go to a world trouble spot and volunteer.

“I thought, no I’ll just go and be a soldier. I want to help so I’m just going to go be a soldier,” he told Australian English teacher Mark Lowe, a pro-Russian blogger.

Oscar Jenkins was jailed after being captured by Russia serving as a soldier for Ukraine. Credit: Supplied

Lowe said Jenkins was physically well but there are fears for the teacher’s mental health.

Jenkins has told his captors he would fight for Russia too.

“I’ve written a statement saying that I’d be happy to fight as a soldier for Russia,” Jenkins said.

It is unclear whether Oscar Jenkins was coerced, influenced or even threatened in any way by Russian authorities over the interview, and experts warn his words should be treated with caution.