A man held hostage by an Isis-affiliated group in the Philippines managed to slip away from his captors and swim to freedom.

Heri Ardiansyah made his escape as marines attempting a rescue battled with members of the Abu Sayyaf terror group on Simusa island in southern Sulu province.

He was later plucked from the waters by marines on board a gunboat.

His fellow Indonesian national, Hariadin, was not as lucky. Having escaped separately, he drowned, regional military spokesman Lt Col Gerry Besana said.

A Malaysian national, identified as Jari Bin Abudullah, was shot by the militants when he ran away. He was airlifted to Zamboanga City, where he was in critical condition in a hospital, military officials said.

The marines gunned down three Abu Sayyaf captors who were trying to chase the two Indonesians at sea, military officials said.

The hostages were kidnapped off Malaysia’s Sabah state on Borneo island in December last year and taken by speedboat to Sulu, the predominantly Muslim and poverty-wracked province where a few hundred Abu Sayyaf have survived in the jungles despite frequent military offensives.

At least three more hostages are still being held by the group, which has sworn allegiance to Isis and is blacklisted by the US and the Philippines as a terrorist organisation.

As government forces surrounded Simusa island to hunt down the remaining Abu Sayyaf gunmen, Isis claimed in a statement it had killed three and wounded 13 Philippine soldiers, but it said “the mujahideen returned safely to base”.

The terror group has a brutal history of bombings, ransom kidnappings, extortion and beheadings.

Army troops clashed with about 80 Abu Sayyaf gunmen in Sulu’s mountainous Patikul town in a fierce but brief gun battle on Friday, the military said, adding that three soldiers and four militants had died in the skirmish and several had been wounded on both sides.

The rebels belong to an Abu Sayyaf faction led by commander Hajan Sawadjaan, who is the main suspect in January’s bombing of a Roman Catholic cathedral in Sulu’s capital Jolo.

Twenty-three died in the attack, along with two suicide bombers.

Additional reporting by Associated Press