The Abu Sayyaf terrorist group has released one of two Malaysians they seized last May from a resort in Malaysia's Sabah state, reportedly after receiving some 30 million pesos (S$900,000) in ransom.

Ms Thien Nyuk Fun, 50, manager of the Ocean King Seafood Restaurant in Sandakan town, Sabah, was released in the southern Philippine town of Indanan on Jolo island at around 11pm on Sunday.

By early yesterday, Ms Thien was safely back home, after an eight-hour speedboat ride from Jolo to Sabah.

Malaysia's The Star newspaper reported that she was "disoriented but generally well", after nearly six months in captivity.

Negotiations were said to be under way to free the second hostage, engineer Bernard Then, 39.

Disagreements among Abu Sayyaf factions were complicating efforts to secure his release, according to The Star.

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

The Abu Sayyaf last month threatened to behead the two hostages, as security forces closed in on the sub-group holding them.

The situation escalated after another faction took to Jolo two Canadians, a Norwegian and a Filipino they kidnapped from an upscale resort in Samal town, Davao province, also in southern Philippines. The Philippine military rejected the militants' demand to start negotiations and halt their offensive.

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

Sulu Vice-Governor Abdusakur Tan was said to have helped negotiate Ms Thien's release through one of his security aides. Two Malaysian security officials reportedly accompanied the Vice-Governor's aide to a meeting point set by the Abu Sayyaf, where the ransom was handed over.

Intelligence officials have linked the sub-group that abducted Ms Thien and Mr Then to a series of cross-border kidnappings in Sabah.

The same men were allegedly behind the abduction of Ms Gao Huayun, a Chinese, and a Filipino resort worker, Ms Marcy Dayawan, in April last year.

Ms Gao and Ms Dayawan were taken from the Singamata Adventures and Reef Resort in Semporna town. They were released two months later, after Ms Gao's family reportedly paid a ransom of about 300 million pesos.

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.