Photo of boy holding decapitated head is barbaric - Australia PM

Australian Prime Minister Tony Abbott delivers his keynote speech during the B20 Summit in Sydney, July 17, 2014. REUTERS/Lisa Maree Williams/Pool

SYDNEY (Reuters) - The photograph of a young boy holding the decapitated head of a slain Syrian soldier and published in Australian media on Monday underscored the barbarity of Islamist State militants, Australian Prime Minister Tony Abbott said.

The image was posted on Twitter and showed the boy, believed to be the son of Sydney jihadist Khaled Sharrouf, The Australian newspaper said, adding that the boy was aged 7.