At least 19 Army soldiers were also wounded and another trooper was reported missing in the clash following a military offensive targeting the Abu Sayyafs mountain lair in Patikul town last Friday, the military said.
Soldiers, backed by police, swooped down on the rebel lair but were met by heavy gunfire from some 300 extremists led by Abu Sayyaf commanders Galib Andang and Mujib Susukan, the military said.
"The fighting was really fierce. Our soldiers were fighting 300 rebels who were heavily armed, but the enemies did not know that government reinforcements had arrived and that the second wave of assault proved fatal to the Abu Sayyaf," one Army official, who declined to be identified, said.
Lt. Gen. Gregorio Camiling, chief of the Armed Forces Southern Command, said the soldiers, belonging to the Armys 4th Infantry Battalion, were pursuing the extremists to rescue Norhana Daud, 24-year-old daughter of Tapul Mayor Hadjie Tulawi Daud, whom Susukans group seized in Patikul last Feb. 18.
Probers said Susukan forced the woman to elope with him after her family junked his marriage proposal. Susukan and the woman are second-degree cousins and were sweethearts during their younger days.
Last year, Susukan and Andang spearheaded an Abu Sayyaf kidnapping spree in which dozens of foreign and local hostages were snatched in two cross-border raids to nearby Malaysian resorts.
Most of the hostages were released after huge ransoms were reportedly paid while others were either rescued or escaped after a military assault was launched last September.
Two hostages, American Jeffrey Schilling and Filipino Roland Ullah, however, still remain in Abu Sayyaf hands and are believed being kept in Jolos jungle areas.
Villagers reported to police that the rebels killed last Friday were dragged away by their escaping comrades and returned to their families.
The Abu Sayyaf is one of two Muslim insurgent groups waging a rebellion for the establishment of an independent Islamic state in Mindanao.
The larger Moro Islamic Liberation Front (MILF), with 12,500 fighters, is set to resume peace talks with the government after President Gloria Macapagal-Arroyo announced a unilateral ceasefire against them. Roel Pareño, Jaime Laude