Canberra says it is working to verify reports that two of Australia's most wanted Islamic State fighters, notoriously pictured holding severed heads, have been killed.
The Australian Broadcasting Corporation cited people close to the families of Khaled Sharrouf and Mohamed Elomar as saying the pair died in fighting in the Iraqi city of Mosul in the past week.
Foreign Minister Julie Bishop confirmed there had been recent drone strikes in the area but said she was still awaiting "absolute verification" they were dead.
Sharrouf gained global infamy last year when he posted pictures on his Twitter account showing himself and his 7-year-old, Sydney-raised son holding up the severed heads of slain Syrian soldiers.
Dressed like any other youngster in blue checked trousers, a blue shirt and baseball cap, the picture of the child was captioned, "That's my boy."
U.S. Secretary of State John Kerry called the grisly photo "stomach-churning."
Elomar, who reacted to the photo of the boy with a tweet to "keep them heads rolling," has also been pictured holding the heads of pro-Syrian fighters.