Australian authorities charged five men with terrorism-related charges Saturday after they were arrested earlier this week for attempting to sail to Indonesia and then travel on to join Islamist groups in Syria.
The men, including radical jihadist preacher Musa Cerantonio, could face a maximum sentence of life in prison if found guilty.
They are scheduled to appear in a Queensland state court Monday.
"The men ... were each charged with one count of making preparations for incursions into foreign countries for the purpose of engaging in hostile activities," the Australian Federal Police said in a statement.
All five men were arrested Tuesday after towing a seven-meter boat almost 3,000 kilometers from Melbourne to Cairns, where they planned to set sail to Indonesia.
The men’s passports had been suspended several months ago, “because the relevant level of concern about their intentions were known to us," Australia’s Attorney General George Brandeis said.
"There is a number of people in Australia under surveillance, and in the event that they were to attempt a terrorist crime, or to attempt to leave Australia in order to perpetrate terrorist war fighting overseas, then they would be taken into custody," Brandeis said.
Australia has been on a heightened alert for homegrown terrorism since September 2014, when it raised its terror threat level to high.
Since then, it has passed several laws aimed at curtailing terrorism, including the law that allowed it to cancel the passports of suspected extremists.
During that time, authorities have also conducted a series of counterterrorism raids across the country, arresting at least several people on suspicion of planning domestic terrorist attacks and involvement with Islamic militants fighting in Iraq and Syria.
Cerantonio, the radical Islamic preacher and vocal supporter of the Islamic State group, was previously arrested in the Philippines in 2014 and deported to Australia due to his support for the extremist group.