MANILA (PHILIPPINE DAILY INQUIRER/ASIA NEWS NETWORK, REUTERS) - An Abu Sayyaf member who is also a relative of Isnilon Hapilon, one of the top leaders of the Marawi siege, has surrendered to the authorities in the southern city of Basilan, the military said.

Ben Salina Sapilin, a cousin of Hapilon, turned himself over to the headquarters of the Army's 74th Infantry Battalion in Al-Barka on Tuesday (Oct 17), Joint Task Force Basilan Col. Juvymax Uy said Wednesday (Oct 18).

Hapilon, who was killed by authorities last Monday, was an Abu Sayyaf leader based in Basilan before he moved to Central Mindanao late 2016.

He was wanted by the United States and was the Islamic State in Iraq and Syria's (ISIS) South-east Asian "emir". Hapilon and Omarkhayam Maute, one of two brothers central to the alliance, were killed in a targeted operation on Monday, five months after they led rebels in occupying the southern city of Marawi.

A day after Hapilon's killing, Philippine President Rodrigo Duterte declared Marawi liberated from pro-ISIS militants, although the military said 20-30 rebels were holding about 20 hostages and still fighting it out.

The 148-day occupation marked the Roman Catholic-majority Philippines' biggest security crisis in years and triggered concerns that with its mountains, jungles and porous borders, the island of Mindanao could become a magnet for Islamic State fighters driven out of Iraq and Syria.

More than 1,000 people, mostly rebels, were killed in the battle and the heart of the city of 200,000 has been levelled by air strikes.

Joining Sapilin in surrendering on Tuesday were Rami Ben Sapilin and Muhammad Endeng, also members of the Abu Sayyaf.

The Abu Sayyaf members also turned over one M16 A1 rifle, one 30 caliber M1 garand rifle, and one M79 rifle.

Uy urged other Abu Sayyaf members in Basilan to return to the folds of law.