KEY POINTS:
- Sage O'Donnell's mother said her son "died in action" in Ukraine.
- DFAT is providing the family with consular support.
- Mr O'Donnell is understood to have served in the Australian Army.
An Australian man has died "in action defending the freedom of the Ukrainian people", the Department for Foreign Affairs and Trade (DFAT) said.
The grief-stricken mother of Sage O'Donnell, issued a statement via DFAT which is providing consular assistance to the family.
"Sage died in action defending the freedom of the Ukrainian people. Sage has always believed in defending country, people and the right for freedom," she said.
Mr O'Donnell's mother described her son as humorous and kind-hearted.
"We are devastated by our recent loss of Sage," she said.
His mother said Mr O'Donnell had served in "his own country" as well as in Ukraine.
It is understood he had been an artillery observer and a rifleman in the Australian Army.
"Sage chose to take action based on his empathy for the Ukrainian people, and the injustice that is taking place.
"He fell in love with Ukraine and its culture, and was humbled by the kindness and hospitality within his new community."
Prime Minister Anthony Albanese has urged Australians who wish to support Ukraine to do so by making financial donations rather than travelling to participate.
"The way that Australians can give support is to give money ... give support to charities and others who are acting in Ukraine not to go and participate in fighting there. It is dangerous," he told Channel Nine's Today show on Thursday.
"I myself, of course, travelled to meet President Zelenskyy earlier this year to show Australia's support.
"I would just say that Australian citizens should follow the advice which is to not travel to Ukraine to participate."
What have Ukrainians in Australia said about Mr O'Donnell's death?
The Australian Federation of Ukrainian Organisations (AFUO) and the Association of Ukrainians in Victoria (AUV) said they were deeply saddened by the news of Mr O'Donnell's death.
"The AFUO and AUV pay respect to the courage and noble values of Mr O’Donnell. His actions show a commitment to the universal values of life, decency, respect and justice," they wrote in a statement.
"Guided by those beliefs, we are honoured that Mr O’Donnell chose to help our country. It is a terrible tragedy that such a fine young man has lost his life fighting to defend Ukraine’s independence and sovereignty.
"We salute him as a hero, and as a community feel deep pain and sorrow that he has paid the ultimate sacrifice for his beliefs."
News of his death had also been shared on social media.
The memorial page for the International Legion Defense of Ukraine posted about the death.
"The Australian Sage O'Donnell, who had been serving in Ukraine as a Volunteer, succumbed on the Battlefield," the post reads.
"Honor, Glory and Gratitude To Our Brother."
The timing of Mr O'Donnell's death remains unconfirmed, but is believed to have occurred in the lead up to Christmas.
In a post on social media, Mr O'Donnell's father said his son had died fighting Russian President Vladimir Putin.
DFAT has not provided any further details about Mr O'Donnell or the circumstances of his death.
