Indonesia launched military exercises in the eastern island of Sulawesi on March 31 as part of broader efforts to crack down on militants with suspected links to the Islamic State (IS) group.

The drills are amid heightened government concerns over a rising number of Indonesians pledging loyalty to IS and attempting to join fighting in Iraq and Syria.

IS is a potential security threat and Indonesia is preparing forces to respond to that, said military spokesman Major General Mochamad Fuad Basya.

He added that the exercises are routine and similar drills will be held elsewhere in the country.

Indonesia has the world's largest Muslim population, the vast majority of which practice a moderate form of the religion.

It saw a spate of militant attacks in the 2000s, the deadliest of which was a nightclub bombing on the holiday island of Bali that killed 202 people, most of whom were tourists.

Police have been largely successful in dismantling domestic militant cells since then.

However, officials now worry about a militancy resurgence inspired by groups like IS and returning Indonesian IS members.-VNA