A video of Australian man Oscar Jenkins being questioned by Russian forces was posted online in December. (Telegram)
In short:
A top official in Kyiv has told the ABC that Russia has "a deep-seated hatred" of foreign nationals fighting for Ukraine.
The warning comes amid reports Vladimir Putin's troops had killed Oscar Jenkins, an Australian they'd captured in Ukraine's Donbas region last year.
What's next?
Australia's Department of Foreign Affairs and Trade (DFAT) is making "urgent enquiries" with Russian authorities about Mr Jenkins' welfare.
Australia's foreign minister Penny Wong has warned Russia that all diplomatic options "are on the table" as officials scramble to verify reports that an Australian man has been killed in Ukraine.
Oscar Jenkins, 32 from Melbourne, may be the first Australian held as a prisoner of war by Russian forces in Ukraine.
On Tuesday, the Australian government confirmed it was making "urgent enquiries" with Russian authorities about a report that a Melbourne man may have been killed.
A DFAT spokesperson said the Seven News report had not been verified. However, they said the government had "grave concerns" for Mr Jenkins.
Senator Wong said she had already called in Russia's ambassador to Australia, and she was considering all diplomatic options including expelling Alexey Pavlovsky.
"I want to be clear, all options are on the table," she told ABC Radio National.
"My thoughts are with Mr Jenkins' family. They've lived with a fear and uncertainty of a loved one in the middle of a foreign war for many months.
Senator Wong also described Australia's relationship with Russia as "difficult".
Russia has "a deep-seated hatred" of foreign fighters like Oscar Jenkins, a top Ukrainian official has warned, as DFAT investigates reports Vladimir Putin's soldiers have killed the captured Australian.
Mykhailo Podolyak, an adviser to Ukrainian President Volodymyr Zelenskyy, also said Moscow's forces do "not adhere to any conventions, including those regarding the treatment of prisoners of war", like Mr Jenkins.
A snap of Oscar Jenkins with colleagues in Ukraine. (Supplied)
Russian soldiers captured the teacher in Ukraine's Donbas region last year.
"The individuals fighting for Ukraine have voluntarily signed relevant legal documents and are fully aware of the risks posed by Russia, not only to Ukraine but to other counties as well," Mr Podolyak told the ABC in Kyiv on Tuesday.
"In my opinion, they are all heroes. Russia has a deep-seated hatred of these foreigners, like Mr Jenkins; people who have made the responsible choice to stand up for the rule of law and freedom by supporting Ukraine."
Mr Podolyak said he "didn't know all the details" about Mr Jenkins' situation.
"While we send our respects to Mr Jenkins' family, we also hope that the global community will respond strongly to Russia's actions, particularly concerning the treatment of prisoners of war," he said.
The Geneva Convention is supposed to protect prisoners of war, like Mr Jenkins.
The December video showed Russian forces interrogating and hitting Mr Jenkins, who had his hands bound with duct tape.
DFAT summoned Russia's ambassador to Australia, Aleksey Pavlovsky, on Monday in a bid to get more information.
Opposition foreign affairs spokesperson Simon Birmingham said the diplomat should be expelled if reports of Mr Jenkins' "extrajudicial execution" were confirmed.
Another foreign fighter who had served alongside Mr Jenkins described him as "the best soldier, man and person you can ever imagine".
Fellow fighters believe Australian killed shortly after capture
Photo shows A man in uniform and a red cap smiles.
"At the end of the day, I'm glad to call him my best friend and my brother," they told the ABC.
Russia's Foreign Minister Sergey Lavrov did not mention Mr Jenkins during a lengthy press conference on Tuesday in Moscow, local time.
The last time Russia's government provided an update was on December 25, when spokeswoman Maria Zakharova confirmed Australia had contacted her country's foreign ministry seeking information about Mr Jenkins.
She said Russia was looking into it.
At least seven Australians are thought to have been killed while fighting for Ukraine since Russia's full-scale invasion of the country began in February 2022.
But Mr Jenkins, a teacher who'd been living in China since 2017, would be the first Australian prisoner of war killed by a foreign power in more than 70 years.
