Two militiamen were also wounded in the raid on an Abu Sayyaf hideout near Barangay Kumalarang in Isabela City.
Armed Forces Southern Command chief Lt. Gen. Ernesto Carolina said three of the slain bandits were identified as Abu Black, Abu Mon Tailani, and Abu Mong.
Troops from the 24th Special Forces company attacked the Abu Sayyaf band led by Hamsiraji Sali after tracking them down to their hideout, according to Maj. Gen. Glicerio Sua, commander of Task Force Comet, the military unit running after the Abu Sayyaf.
"We have been monitoring this group of Hamsiraji Sali, about 10 to 15 of them, and we initiated the offensive operation leading to the encounter this morning," he said.
Sua said troops recovered the bodies of the four slain Abu Sayyaf fighters, but he did not say if one of those killed was Sali.
"Pursuit operations are continuing with the remaining Abu Sayyaf forces," he said.
Carolina said Sali escaped during the fighting and that it could not be determined if he had been wounded as troops continued pursuit operations. — Roel Pareño, Paolo Romero, AFP