Child Holding Severed Head 'Grotesque, Disturbing'

U.S. Secretary of State John Kerry says a photo of a 7-year-old boy proudly holding the severed head of a Syrian soldier shows why the Islamic State, also known as ISIS, poses a threat not just to Syria and Iraq, but to the world.

The Australian boy's terrorist father, Khaled Sharrouf, posted the image to Twitter and captioned it "That's my boy."

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

"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.

Australian Foreign Minister Julie Bishop said the image is "truly shocking."

"A 7-year-old child is involved in this barbarous display of ideology and they're Australian citizens. Our fear is that they will return home to Australia as hardened, homegrown terrorists and seek to continue their work in Australia -- and it's not a concern just of this country," Bishop said.

Bishop noted that "a significant number" of convicted terrorists would soon be released from Indonesian prisons.

"It's a shared issue across Australia, Indonesia, Malaysia, Philippines, Europe, in Pakistan, in Great Britain, Canada -- there are a number of countries across the globe reporting instances of citizens becoming extremist fighters in the Middle East," Bishop said.

Kerry has proposed that the United States and Australia take the issue to the United Nations so countries can protect themselves from fighters coming back from Syria and Iraq.

The secretary of state limited his remarks to ISIS, not mentioning other Islamic terror groups, such as Hamas. The group sponsors summer training camps where children are taught how to carry out terror attacks against Israelis.