A 17-year-old Australian fighting with Islamic State (IS) has appeared in a propaganda video in which he tells Prime Minister Tony Abbott they will never stop fighting.
Australian security agencies believe the speaker is Abdullah Elmir, who went missing from his home in Sydney's west at the end of June, the ABC reports.
In the video he delivers a message specifically mentioning Mr Abbott and Australia.
He also says IS will fight until the black flag is flying over Buckingham Palace and the White House.
Elmir disappeared in June, along with another Australian boy, aged 16.
It is believed the pair travelled to Turkey and then crossed the border into Syria.
The 16-year-old was later intercepted by his father and has since returned to Australia.