WASHINGTON - A young American who assumed the online identity of an Australian jihadist has been arrested for an alleged plan to bomb a September 11 memorial event, authorities said.
Joshua Ryne Goldberg, who was arrested in Florida, has admitted to providing instructions on how to make a pressure cooker bomb with the intent "to kill and injure persons," according to court doucments.
The 20-year-old's directives included instructions on how to fill the bomb "with nails, metal and other items dipped in rat poison," to be placed at a September 11 memorial in Kansas City, Missouri, the US Department of Justice said.
He could face up to 20 years in prison if convicted, the department said.
Australian Federal Police confirmed they had helped the Federal Bureau of Investigation track down the 20-year-old man.
They alleged that Goldberg, who posed online as "Australi Witness," had "provided information over the Internet in an attempt to facilitate and encourage terrorist acts in Australia" as well.
Goldberg's arrest, which was authorised Wednesday by a US judge, came as Americans prepared for the 14th anniversary of the September 11 attacks that brought down the World Trade Center in New York and destroyed part of the Pentagon, killing nearly 3,000 people.
Australian authorities, who raised the nation's terror alert to high a year ago, said US investigators took over when the Australians determined the person responsible for the threats was likely in the United States.
Australian Federal Police's acting deputy commissioner for national security Neil Gaughan said the alleged assailant 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 sympathizers 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.