A South Korean who was kidnapped by Muslim extremists in the southern Philippines in January has been found dead, police and military officials said Sunday.

The hostage, Hong Nwi-Seong, whose age was given as 70, was discovered in Patikul town on the strife-torn island of Jolo on Saturday, more than nine months after he was seized by members of the Abu Sayyaf group, said Brigadier General Alan Arrojado, commander of a special anti-terror task force.

Arrojado said the victim was not killed but that the Abu Sayyaf had brought his body to the area "after the subject's death due to severe illness."

The type of illness was not disclosed but local military spokesman Captain Antonio Bulao said the South Korean had been reported to be sick for the past few weeks and had died three to five days ago.

The victim was seized from his home in the Zamboanga peninsula by armed men on January 24 and was later reported to be in the hands of Abu Sayyaf commanders, the military said.

Details of his confinement and efforts to free him were kept quiet to avoid endangering the hostage.

His body had been transferred to the southern city of Zamboanga and would be flown to Manila, the authorities said.

A South Korean foreign ministry official, who declined to be identified, had earlier confirmed the death, South Korea's Yonhap News Agency reported.

It identified the victim as a "74-year-old... surnamed Hong," adding that "if the body turns out to be our national, we will investigate with the Philippines authorities on how he died and in what circumstances."

South Korean embassy spokesmen in Manila could not be contacted for comment.

Founded in the early 1990s with seed money from Al-Qaeda chief Osama bin Laden, the Abu Sayyaf has been blamed for the Philippine's deadliest terror attacks including the kidnapping for ransom of foreigners, some of whom they killed.

The heavily-forested island of Jolo is their stronghold where they often hide their hostages for months.

The group is believed to be behind the recent kidnapping of three Westerners and a Filipina taken in September and the abduction of an Italian restaurant owner in October, all from the southern Philippines.

They are also believed to be already holding a Dutch bird watcher, two Malaysians, and a Filipino boy.