MANILA, April 24 (Xinhua) -- Abu Sayyaf militants had beheaded a Filipino soldier who was abducted Thursday, a military general said Sunday.

Brig. Gen. Cirilito Sobejana, commander of the Joint Task Force Sulu, said in a statement that troops found the body of Army Sergeant Anni Siraji in a remote village around 3 p.m. on Sunday.

The decomposed state of the body of the victim suggested that he had been beheaded for at least three days and his body was found some 2.5 km from where he was abducted, the general said, adding the severed head was found some 50 meters away from the decomposed body.

"They attempted to bring the head but they eventually left it behind. You can see that the beheading was hastily done maybe because they were running away from us."

Siraji is a member of the Tausug tribe, an ethnic group in southern Philippines. He was kidnapped on Thursday morning at the height of the military operations against the bandit group Abu Sayyaf in Patikul town in Sulu.

Siraji was a former member of the Moro National Liberation Front (MNLF). He, along with several other MNLF fighters, was integrated into the military as part of the 1996 peace agreement the MNLF signed with the government.

The military said Patikul town is one of the main targets of the military offensives since January as it is reported to be a stronghold of the Abu Sayyaf.

Some of the Abu Sayyaf members are also Tausug, according to the military.

The Abu Sayyaf bandits are most probably frustrated that they were forced to kill a member of their own tribe, Sobejana said.

"We condemn this barbaric act of killing their fellow Tausug."

The military has been fighting the Abu Sayyaf rebels since 2000.

Abu Sayyaf, one of the smallest and most violent groups operating in southern Philippines, is notorious for kidnappings, bombings and attacking civilians and the army.

The group, numbering about 500, has been sowing terror in southern Philippine since the early 1990s. The military said they are still keeping more than two dozens of hostages.

Responding to the barbaric act by Abu Sayyaf, Philippine President Rodrigo Duterte has ordered the military to crush the Abu Sayyaf militants.