The Philippine military said it has launched search and rescue operations for five Indonesian fishermen kidnapped by Islamic State-linked Abu Sayyaf militants in Malaysian waters last week.

Eight Indonesians were abducted in Sabah on Thursday. Three were released, while the remaining five were probably brought by their captors to the southern Philippine province of Sulu, said Lieutenant General Cirilito Sobejana, chief of the military’s Western Mindanao Command.

Sulu is Abu Sayyaf’s stronghold.

Sobejana disclosed the abduction a day after soldiers clashed with Abu Sayyaf members in Sulare island in Parang town, in Sulu, killing one militant and destroying a speed boat believed to have been used in the kidnapping.

Sobejana said Malaysian authorities had immediately coordinated with the Philippine military after the abduction.

Indonesia’s foreign ministry said it also has coordinated with the Philippine government and was still waiting for official information about the incident.

The speed boat was positively identified by the three Indonesian fishermen who have been freed as the one used in the abduction staged by six militants, Sobejana said.

“The likelihood they are in Sulare island or Parang, Sulu is very high,” he said.

Abu Sayyaf, which has its roots in separatism, is notorious for banditry and piracy, including beheading some captives if no ransom is paid. — Reuters