GRUESOME photos of an Australian brandishing severed heads of Syrian government soldiers has sparked a warning from Prime Minister Tony Abbott that terrorists will be jailed.
"I have a very strong message for any Australian who is thinking of going overseas to engage in guerrilla warfare, Jihadism, anything of this nature: don't do it. It is a serious crime and if you come back to Australia you will be arrested, you will be charged, you will be jailed,'' Mr Abbott said.
"This is a serious crime. We do not want Australians going abroad to fight in other people's wars - we do not.
"We do not want it done and if you do it - you are doing wrong and you will suffer the consequences."
His comments come after the Australian Federal Police issued arrest warrants for the two most prominent Australians fighting for a banned terrorist group in Syria and Iraq.
The ABC reported there is deepening concern among intelligence agencies about the potential for the bloody Syrian and Iraqi civil wars to spill over onto Australia's shores.
Attorney-General George Brandis said the threat presented by returning Islamist fighters is the greatest threat to Australian security in years.
The ABC's 7.30 program reported the AFP had issued warrants seeking the immediate arrest of Khaled Sharrouf and Mohamed Elomar for terrorism offences if they return to Australia.
The two Sydney men travelled to Syria and then Iraq late last year and joined the most vicious of the Al Qaeda-linked groups fighting there, the Islamic State, formerly known as ISIS or ISIL.
It came after a Twitter account, purporting to belong to Sharrouf, published photos on Thursday and Friday of Elomar holding the severed heads of Syrian government soldiers.
In one photo Elomar holds up two severed heads. In another, he presents one head to the camera, with another three on the floor beside him.