An Australian nurse was charged with supporting the Islamic State militant group fighting in Syria during a brief court appearance on Sunday, police said.
The nurse, who has been identified as 39-year-old Adam Brookman, was arrested in Sydney soon after he returned from Syria via Turkey on Friday night. He was transferred to appear in court in Melbourne, Australia's second-largest city, at the request of an anti-terrorism task force based there.
"It will be alleged that the man, while in Syria, knowingly provided support to the terrorist organization known as Islamic State," the Australian Federal Police (AFP) said in a statement.
The Sydney Morning Herald reported the charge carries a maximum sentence of 25 years in jail.
The charges also include "performing services with the intention of supporting a person to engage in a hostile activity in a foreign state", the AFP said.
Brookman, a father of five, has told Australian media he went to Syria on a humanitarian mission and had been forced to join the militant group after he had been wounded.
Australia is on high alert for attacks by radicalized Muslims, including home-grown militants returning from fighting in the Middle East. It has raised its threat level to "high" and launched a series of high-profile raids in major cities.
Prime Minister Tony Abbott has said at least 70 Australians were fighting in Iraq and Syria, backed by about 100 Australia-based "facilitators".
Abbott has secured a raft of new security powers in recent years, expanding domestic spying capabilities and proposing to strip citizenship from dual nationals accused of committing violent militant acts.
Brookman surrendered himself on Tuesday to officials in Turkey, who helped negotiate his return. He is due to appear in court in Melbourne again on Monday.
Police said there was "no evidence of a threat in Australia in this instance".