'Australian' jihadist was young American: report

A young man who allegedly assumed the online identity of an Australian jihadist supporting Islamic State has been revealed to be an American living at his parents' house, a report said today.

Australian Federal Police confirmed they had helped the Federal Bureau of Investigation track down a 20-year-old man in Jacksonville, Florida who had allegedly provided information to facilitate terror attacks in the US and Australia.

"The man was arrested for distributing information relating to explosives and destructive devices to facilitate a possible terrorist act in the United States," they said in a statement to AFP, adding he faced a 20-year prison term if convicted.

"It will also be alleged that this person provided information over the Internet in an attempt to facilitate and encourage terrorist acts in Australia."

Australian authorities, who raised the nation's terror alert to high a year ago, said when their investigations determined the person responsible for the threats was likely in the United States, their American counterparts took over.

Australian authorities did not reveal the man's identity, but Fairfax Media named him as Joshua Ryne Goldberg, who they said had been posing online as "Australi Witness".

The media outlet said "Australi Witness" had allegedly distributed pictures of a bomb he was building which he said had "2 lbs of explosives inside".

It said he was accused of instructing someone on how to make a bomb from a pressure-cooker, and to fill it with nails and other metal pieces dipped in rat poison.

Australian Federal Police acting deputy commissioner for national security Neil Gaughan said the man involved had presumed he was safe.

"This man thought that he could willingly and maliciously distribute disturbing information via the Internet and never have his identity discovered," Gaughan said.

"This operation again highlights how law enforcement can investigate people in the online space and use our long-established partnerships to work with overseas agencies to bring people to account for their actions."

Australia, which is part of the US-led coalition against Islamic State in the Middle East, has been increasingly concerned about the radicalisation of its youth.

Some 120 Australians are still fighting with IS in Iraq and Syria, while at least 30 have been killed. Another 160 sympathisers are believed to be supporting jihadists from home.
To combat the problem, Canberra has raised its terror threat alert level to high, introduced new national security laws and conducted several counter-terrorism raids.