SYDNEY – Five men were detained by Australia’s police suspected of planning to travel to Syria to join ISIS through a small motor boat that was supposed to take them to Indonesia and the Philippines before they proceed with their journey. Neither of the men had their names revealed, however they were arrested on Tuesday following their first ,3000 km (1,865 miles) from Melbourne to Cairns in northern Queensland state.

Later all five, the youngest aging 21 and oldest 31, were charged on Saturday with preparing to enter a foreign country “for the purpose of engaging in hostile activities,” an offence that carries a maximum penalty of life imprisonment, and shall appear in court on Monday. Meanwhile, the men remain in custody.

There is no current threat of a terrorist act to the Australian community arising from this investigation, according to police.

The plan the men had been already clear by the police; Australian Attorney-General George Brandis told reporters on Sunday “their intentions to travel to the Middle East to engage in terrorist war fighting were known to the authorities,” and that their passports had earlier been cancelled.

Brandis said that when it became clear to the men they could not leave “in an orthodox way, they remained under surveillance so that if they attempted to leave the country in this very unusual way they would be able to be stopped and they were.”

There is “an unusual character to the plot, I know it has been ridiculed, but these are serious crimes,” he said.

Australia, a staunch U.S. ally, has been on heightened alert for attacks by home-grown radicals since 2014 and authorities say they have thwarted a number of potential ones.

Almost 100 people have left Australia to fight in Syria along groups like ISIS, Australia’s Immigration Minister said last month. Police said earlier this week that it was unclear where the men had planned to put the boat in the water. Indonesia and Australia share a maritime border, but it spans several hundred kilometres of open sea at its narrowest point.

The Australian Broadcasting Corporation said Melbourne-born radical preacher Musa Cerantonio, a vocal supporter of ISIS who was deported from the Philippines to Australia in 2014, was among those charged. Police declined to comment on the report.

On Sunday, Australian Foreign Minister Julie Bishop said she will said attend Syria peace talks in Vienna on Tuesday co-chaired by US Secretary of State John Kerry and Russian Foreign Minister Sergey Lavrov