School playgrounds being used for terrorism recruitment, minister warns

School playgrounds are being used as potential terrorism recruitment centres, with graphic videos being shared with vulnerable children, the federal government has warned.

Home Affairs Minister Clare O'Neil has joined the nation's spy chief in warning terror groups are converting Australian teenagers as young as thirteen.

She told the Australia-NZ Counter Terrorism Summit on Thursday that she was recently briefed by ASIO about a case involving teenagers radicalising children in the school playground.

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In the case, a group of teenagers targeted lonely or vulnerable children, including those who had been bullied, and flattered them with compliments to befriend them.

The teens then manipulated their targets, showing them increasingly violent Islamic State propaganda videos including beheadings.

"We're seeing these presentations in children that are younger and younger," O'Neil said.

"And it's something we really want the community to be thinking about and talking about."

More than half of ASIO's highest priority investigative cases are minors, some as young as 13 years old.

ASIO Chief Mike Burgess already voiced his concerns about young Australians being recruited by extremists back in February.

"As the director general of security... this trend is deeply concerning," he said.

"Unlike past experience, many of these young people do not come from families where a parent or sibling already holds extreme views."