JAKARTA/SERDANG • The Indonesian authorities are investigating whether a suspected militant arrested last week was planning an attack on the resort island of Bali.

Bali, a popular tourist destination, saw a number of attacks by home-grown militants in the early 2000s, the deadliest being a nightclub bombing that killed 202 people - most of whom were Australians.

Police found a bomb and "high impact explosive materials" during a raid on the suspect's house on the western island of Sumatra, media said.

The man, whom police have yet to identify, was arrested after he was suspected of having links to the extremist Islamic State in Iraq and Syria (ISIS) group.

He is also suspected of being involved in a suicide bombing at a police station in the central Javanese city of Solo last month. Only the bomber was killed in the Solo attack, and a police official was wounded.

Mr Edy Hartono, chief of the counter-terrorism police unit, said police were looking into the suspected Bali plot.

"It was still just a plan," he told Reuters, declining to elaborate.

The arrest in Lampung, Sumatra, was among a series of terrorism-related arrests across several cities in Indonesia last week as the authorities intensify a security crackdown in the world's largest Muslim-majority country.

Indonesia saw its first ISIS-linked attack in January when four militants mounted a gun and bomb attack in a busy commercial district in the capital Jakarta.

Eight people were killed, including the militants.

Malaysia, which is also battling the threat of extremism led by ISIS, saw its first strike linked to the militant group on June 28, when two militants tossed a grenade into a night spot in Puchong, Selangor, injuring eight people.

Deputy inspector-general of policeNoor Rashid Ibrahim said the police are keeping a close watch on university students who may have been influenced by ISIS ideology as the terrorist group targets mainly youth and tertiary students.

"We have even arrested people as young as 16 years old... over alleged links," he told reporters yesterday.

"Even some of them who just happened to 'like' a sympathetic post about IS on social media are watched," he said, using another acronym for the militant group.

REUTERS, THE STAR/ASIA NEWS NETWORK