Islamist militants in the Philippines on Tuesday (Nov 17) beheaded the remaining Malaysian hostage they seized in May from a resort in Malaysia's Sabah state.

Brigadier-General Alan Arrojado, commander of the Joint Task Group Sulu, said Mr Bernard Then, 39, an engineer, was beheaded at around 4pm at a remote Abu Sayyaf stronghold in Jolo island, in Sulu province, some 1,400km south of the capital Manila.

He said Mr Then's family "failed to comply" with the militants' demand "during their negotiation that prompted them to execute their plan".

"Accordingly, the body was immediately buried in the vicinity where they beheaded the victim," he said.

He said efforts were now being undertaken to locate Mr Then's remains.

Mr Then was beheaded more than a week after the Abu Sayyaf released Ms Thien Nyuk Fun, 50, manager of the Ocean King Seafood Restaurant in Sandakan town, Sabah, reportedly after receiving some 30 million pesos (S$900,000) in ransom.

Mr Then and Ms Thien were taken from the same resort.

Mr Then was reportedly suffering from leg injuries he sustained while in captivity, and had been slowing down his captors.

The Abu Sayyaf had threatened to behead him just after releasing Ms Thien.

Mr Then was beheaded just hours after Malaysian Prime Minister Najib Razak landed in Manila for the two-day summit of the Asia-Pacific Economic Cooperation forum.

Police identified the leaders of the group behind the Sandakan abduction as Alhabsy Misaya, Alden Bagade and Angah Adji.

The Abu Sayyaf was formed by disgruntled Moro Islamic fighters in 1991, with Al-Qaeda funding. However, it did not gain prominence till May 2000, when it attacked a dive resort in Sipadan, Malaysia, taking 21 hostages.