CANBERRA, Australia (AP) — US Secretary of State John Kerry on Tuesday described a photograph of a Sydney-born 7-year-old boy clutching the severed head of a Syrian soldier as “one of the most disturbing, stomach-turning, grotesque photographs ever displayed.”

The Australian newspaper reported Monday that the image was taken in the northern Syrian city of Raqqa and posted on Twitter by the boy’s convicted terrorist father, Khaled Sharrouf, an Islamic State fighter.

Speaking after a US-Australia bilateral security summit in Sydney, Kerry said the image showed why the Islamic State group posed such a threat to the world.

He proposed taking the issue of foreign fighters to the United Nations so that countries could agree on ways to protect themselves from the terrorist threat from fighters returning from Syria and Iraq.

An edited photograph of a Sydney-born 7-year-old boy clutching the severed head of a Syrian soldier, presumably in Raqqa, Syria (photo credit: Twitter)

An edited photograph of a Sydney-born 7-year-old boy clutching the severed head of a Syrian soldier, presumably in Raqqa, Syria (photo credit: Twitter)

“This image, perhaps even an iconic photograph … really one of the most disturbing, stomach-turning, grotesque photographs ever displayed,” Kerry told reporters.

“Of a 7 year-old child holding a severed head up with pride and with the support and encouragement of a parent, with brothers there,” he said.

“That child should be in school, that child should be out learning about a future, that child should be playing with other kids, not holding a severed head and out in the field of combat,” he said.

The child’s grandfather, Sydney truck driver Peter Nettleton, told The Australian newspaper that he was “gutted” to see the photo on the newspaper’s front page on Monday showing his grandson holding the head up in the air with both hands.

Nettleton, father of Sharrouf’s Anglo-Australian wife Tara Nettleton, told The Daily Telegraph newspaper he had thought his five grandchildren had been living in Malaysia while Sharrouf fought with the Islamic State army in Syria and Iraq.

US Secretary of State John Kerry, left, talks with Qatari Foreign Minister Khaled al-Attiyah Saturday, July 26, 2014, at the US ambassador's residence in Paris (photo credit: AP/Charles Dharapak)

US Secretary of State John Kerry, left, talks with Qatari Foreign Minister Khaled al-Attiyah Saturday, July 26, 2014, at the US ambassador’s residence in Paris (photo credit: AP/Charles Dharapak)

“I’m scared for the children,” Peter Nettleton told the newspaper. “What life are they going to have now?”

“Can’t the government do something to pull these kids away from that man?” he asked.

Nettleton could not be immediately contacted for comment Tuesday.

Sharrouf, 33, also posted a photograph of his three sons posing with him in matching camouflage fatigues and armed with assault rifles and a pistol with an Islamic State flag as their backdrop. He also has two daughters, The Daily Telegraph reported.

Nettleton said he became estranged from his daughter nine years ago after she converted to Islam and married her teenage sweetheart, an Australian born to Lebanese immigrants.

Australia’s Foreign Minister Julie Bishop told Australian Broadcasting Corp. that the family could face legal action if they returned to Australia. She did not say whether her government would make an effort to secure the children’s return.

The domestic terrorism threat posed by homegrown jihadists was a focus of annual bilateral talks on Tuesday between Bishop, Kerry, US Defense Secretary Chuck Hagel and his Australian counterpart David Johnston.

Sharrouf used his brother’s passport to leave Australia last year. The Australian government had banned him from leaving the country because of the terrorism threat he posed.

Sharrouf was among nine Muslim men accused in 2007 of stockpiling bomb-making materials and plotting terrorist attacks in Australia’s largest cities, Sydney and Melbourne.

He pleaded guilty to terrorism offenses and was sentenced in 2009 to four years in prison.

Australian police announced last month that they had arrest warrants for Sharrouf and his companion Mohamed Elomar, another former Sydney resident, for “terrorism-related activity.”

They will be arrested if they return to Australia.

The warrants followed photographs being posted on Sharrouf’s Twitter account showing Elomar smiling and holding the severed heads of two Syrian soldiers.

Copyright 2014 The Associated Press