An Australian man, Trevor Kjeldal, has died in Ukraine, according to the Department of Foreign Affairs and Trade (DFAT).
The ABC understands the man had been fighting in Ukraine when he was killed.
A DFAT spokesperson said officials were "providing consular assistance" to the man's family.
"We send our deepest condolences to the family and request their privacy be respected during this difficult time," the spokesperson said.
"We are unable to provide further comment."
His family confirmed his death in a statement.
"Trevor was a very treasured and loved member of our family," a family spokesperson said.
"Our depth of sadness at his loss is unfathomable."
"We would like to thank DFAT for their ongoing assistance in bringing him home to us."
Speaking at a press conference on Queensland's Sunshine Coast, Prime Minister Anthony Albanese described the man's death as "tragic news".
"My condolences go to this gentleman's family and his friends," he said.
"I remind people that the DFAT advice is that people do not travel to Ukraine. It is a dangerous place.
"My heart goes out to the family and friends of the gentleman involved."
The federal government's travel advice for Ukraine remains "do not travel".
DFAT's ability to provide consular assistance to those who travel there is extremely limited due to Russia's invasion.
