The Army was on the verge of a "decisive battle" with the Abu Sayyaf guerrillas, but the presence of Moro Islamic Liberation Front (MILF) gunmen in Basilan complicated the situation, a military spokesman said. Civilians are also being evacuated from the conflict areas.
Troops were walking a delicate tightrope, trying to abide by a six-day-old ceasefire aimed at ending a 23-year MILF insurgency, while hunting down the Abu Sayyaf to end a month-long hostage crisis, Brig. Gen. Edilberto Adan said.
"Their presence complicates our work," Adan told dzBB radio, because the MILF risked being caught in a crossfire.
Military intelligence reports said the Abu Sayyaf, holding at least 21 Filipino and two American captives, were trying to draw the Army toward MILF bases to widen the war.
"I heard the MILF on television last night, they were complaining that we are fighting their forces there," Adan said.
"Our answer to them is, why were they there in the first place?"
There have been a series of clashes between government troops and the Abu Sayyaf in recent days as the Army advanced toward the rebels main lair in a mountainous area called Sampinit complex in the center of Basilan.
Although official estimates put the size of the Abu Sayyaf at less than 500, Adan said he believed other armed groups were providing the guerrillas with protection.
"We have more than 1,000 armed elements on the island," Adan said earlier this week.
Remnants of the MILF and the Moro National Liberation Front (MNLF), which signed a peace accord with Manila in September 1996, were also active, he said.
The military, which has poured more than 5,000 troops into Basilan and has been criticized for not ending the hostage crisis sooner, has reshuffled the leadership of the task force closing in on the Abu Sayyaf.
Brig. Gen. Romeo Dominguez was replaced by Brig. Gen. Glicerio Sua, who was responsible for the rescue of many local and foreign hostages held by the Abu Sayyaf on nearby Sulu island last year.
The Army also claimed success yesterday with the arrest of a third Abu Sayyaf member.
Karim Hassim, wanted for a string of kidnappings last year, was arrested at an Abu Sayyaf hideout near the militarys southern command headquarters in Zamboanga.
On Wednesday, the military announced the arrest of another Abu Sayyaf member, Harsim Abdulajid, who they said was in Manila preparing a bombing mission.
Abu Sayyaf intelligence officer Abdullah Yusof, arrested last week, was said to be providing significant leads in the Basilan campaign.
The guerrilla leaders holed up in central Basilan are believed to be holding American missionary couple Martin and Gracia Burnham and eight Filipino hostages. A second rebel unit holds 13 Filipinos elsewhere in the island.
The Burnhams and another American, Guillermo Sobero, were seized along with 17 Filipinos at the upscale Dos Palmas resort in Palawan on May 27. The rebels later snatched four hospital staff and 15 plantation workers in Basilan.
Eleven hostages have escaped or been freed since the crisis began and four Filipinos have been killed. The Abu Sayyaf say they have also beheaded Sobero although his body has not been found.