The remains of two Abu Sayyaf rebels killed in Basilan are presented to the press by (frm left) Southern Command chief Lt Gen Roy Cimatu, Basilan military commander Col Hermogenes Esperon and Task Force Comet chief Brig Gen Glicerio Sua.

Thirteen Abu Sayyaf bandits were killed while 10 others were wounded as government troops in Basilan stepped up efforts to close in on the group and rescue an American couple and a Filipino nurse it has held captive since May.

Southern Command chief Lt. Gen Roy Cimatu said two troopers from the Army's Light Reaction Force and Scouts were wounded when they encountered the Abu Sayyaf's main force headed by Abu Sabaya and his security aide Hamsi Radisali.

According to Cimatu, the fightings started at 6:30 a.m. in Sitio Makiri, Barangay Balawitan, Isabela City in Basilan.

He said Army troopers were patrolling in the outskirts of Makiri when they chanced upon Abu Sabaya's group of 20 bandits.

The soldiers recovered a 90mm recoilless rifle, one M16 and one shotgun. They also found a "thermal imager" similar to a night vision goggles believed to have been taken by the bandits from slain soldiers in previous clashes.

The government troops captured an Abu Sayyaf member who is now helping them search area where his comrades are believed to be hiding.

"The encounter that resulted in the recovery of 90mm recoilless rifle indicates that the group was the one protecting Aldam Tilao or Abu Sabaya and the Burnham couple. The group is being led by a major commander who provides a perimeter security to Sabaya's lair where the hostages are being kept," AFP spokesperson Brig Gen Edilberto Adan said.

Two of the 13 Abu Sayyaf fatalities, Cimatu said, were killed in a separate encounter in Sumisip town in Basilan

The two were believed to be part of Abu Sabaya's perimeter force. No one was reported killed or injured on the side of the government.