Malaysia's prime minister condemned on Wednesday the beheading of a hostage by Abu Sayyaf - the first Malaysian killed by the armed group that operates in the southern Philippines. 

Bernard Then was kidnapped in May from the Ocean King seafood restaurant in Sandakan, Malaysia, with the restaurant's owner, Thien Nyuk Fun.

They had been held for the past six months by the rebel group Abu Sayyaf in remote Philippine jungles on the southern island of Jolo, about 330km from Sandakan.

A severed head was found in a sack with Then's full name on it - "Bernard Then Ted Fen" - by a cleaner outside a local government office on Tuesday night.

Prime Minister Najib Razak, in Manila for the APEC summit, denounced Then's killing.

"I am shocked and sickened by the murder of our countryman Bernard Then and we condemn it in its strongest terms," Najib said on his Facebook page.

Hostage Thien Nyuk Fun was released on November 8 after her family paid a reported ransom. Then's family had been in negotiations with Abu Sayyaf, but these reportedly had broken down.

Then was the first Malaysian killed by the Abu Sayyaf. He had been vacationing in Sandakan with his family when he was grabbed at the restaurant and passed onto Abu Sayyaf fighters.

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Abu Sayyaf has used kidnap for ransom for years as a way of raising funds to support its insurgency.

One of the most notorious abductions was in 2001 when American missionary couple Gracia and Martin Burnham and Filipino Guilllermo Sobrero were snatched from an exclusive resort on Palawan island.

They were taken back to Mindanao and held for about a year until a military rescue operation was launched. Sobrero had been beheaded by that time. Martin Burnham was killed during the rescue.

Source: Al Jazeera