“That’s my boy.”

Those are said to be the proud words of a convicted terrorist who tweeted out a photo of his young son holding up the severed head of a slain Syrian soldier.

The photo, published in The Australian newspaper, reportedly shows the son of Khaled Sharrouf, a Sydney man who fled to Syria last year and joined up with Islamic State militants. The boy, wearing a blue shirt and a blue watch, uses both hands to grab fistfuls of hair to hold the head up for the camera.

Image source: The Australian

Image source: The Australian

According to the newspaper, Sharrouf posted other photos as well, including one posing with his sons, everyone decked out in fatigues and holding guns in front of the IS flag, and another of himself with the same severed head.

“There are more photographs in newspapers in Australia today of the kind of hideous atrocities that this group is capable of,” Australian Prime Minister Tony Abbott told Australian radio. “[The] Islamic State — as they’re now calling themselves — it’s not just a terrorist group, it’s a terrorist army and they’re seeking not just a terrorist enclave but effectively a terrorist state, a terrorist nation.”

Image source: The Australian

Image source: The Australian

The Islamic State, previously known as the Islamic State of Iraq and Syria, has seized significant territory in the region and proclaimed a caliphate. Its gains across Iraq prompted the United States last week to begin a series of airstrikes to impede its advance.

“ISIL is a threat to the civilized world, certainly to the United States, to our interests, as it is to Europe, it is to Australia,” U.S. Secretary of Defense Chuck Hagel said in Sydney. “I think reflected on the local newspaper I saw this morning, with the picture on the front page, it’s pretty graphic evidence of the real threat that ISIL represents.”