JAKARTA - The police anti-terror Detachment 88 has arrested an Indonesian terrorist suspect in a small island on the Indonesia-Philippines border for planning to cross over to join ISIS in Marawi.

The man, identified by Indonesian police by his initial AM, comes from Banten, a neighbouring province of Jakarta. He had travelled to Bitung, North Sulawesi province, and then on a boat to Sangihe island, in the most-northern part of the province, where he was nabbed.

During the interrogation, the man admitted that he would cross over to the Philippines, police spokesman Inspector General Setyo Wasisto told reporters.

"Our preliminary investigation reveals that his planned trip to the Philippines is to join the rebel group in the South Philippines. He is an ISIS supporter," he said.

General Setyo did not say when AM was arrested, but he was flown to Jakarta on Monday (Nov 13) for further investigation.

AM's arrest comes a few weeks after the Philippine security officials declared an end to fierce urban fighting in Marawi, exactly five months after hundreds of pro-ISIS militants stormed the city, in what has become the Philippines' biggest security crisis in years.

Philippine Defence Secretary Delfin Lorenzana had said on Oct 23 that the government terminated all combat operations in Marawi.

The Philippines has "nipped the budding infrastructure and defeated terrorism in the Philippines. There are no more militants inside Marawi," he added.