Australian police arrested a man accused of sending money to Islamist groups in Syria as part of a crackdown on home-grown jihadists.
Hassan El Sabsabi, 23, was held in Melbourne and later appeared before a local court on six counts of intentionally making funds available to a terrorist organisation.
Prosecutors said the arrest was the result of an eight-month investigation that started with a tip-off from the FBI.
El Sabsabi is accused of making several payments to the Islamic State militant group, previously known as Isis, and to al-Qaida affiliate Jabhat al-Nusra.
The money, totalling $12,000 (£7,400), served to support a US national fighting in Syria, prosecutors said.
No details about the suspect American jihadist were given but Federal Police Assistant Commissioner Neil Gaughan said he had been fighting in Syria for "a number of months".
The two men were not related and knew each other through social media, he said.
Police El Sabsabi was about to send more money to Syria as he was arrested but did not represent a direct threat for the local community and operated alone.
"This is a terrorism financing case — we didn't assess there being a significant community safety risk, or a significant risk to our officers," Victoria Police deputy commissioner Graham Ashton said.
El Sabsabi did not enter a plea or apply for bail. If convicted, he could face up to life in prison.
His arrest came a week after security forces in the southern city shot dead an 18-year-old suspect extremist who attacked two officers with a knife upon arriving at a police station for an interview.
Federal Police Assistant Commissioner Neil Gaughan said the two incidents were not connected.
Earlier this month, anti-terror officials carried out a number of raids having apparently received intelligence that IS sympathisers were preparing to snatch an innocent civilian from the streets, behead them on video and wrap them in an IS flag.