The soldiers who were aboard a military vehicle were attacked along the road between the villages of Pamatsaken and Limbo Candis on Wednesday morning.
Reports reaching Camp Aguinaldo identified the fatalities as Pfc. Mahail Jumdana and Pfc. Raja Teajili and civilian Munib Abduho.
The two wounded were Lt. Rajik Misuari, Alpha company commander of the 55th Infantry Battalion, and Pfc. Eddiemar Lahi.
Brig. Gen. Reymundo Ferrer, 103rd Army Brigade chief, said a firefight ensued for about 20 minutes as the wounded soldiers fought the Abu Sayyaf group, reportedly under Commander Amir Mingkong.
Aside from being an Abu Sayyaf member, Mingkong is also believed to be a lost command separatist rebel leader.
It was not immediately known if the Abu Sayyaf group suffered casualty as they fled.
Troops have been on hot pursuit operations against the attackers who are believed holding camp in the Sumisip mountains, according to Ferrer.
Ferrer warned soldiers in Basilan not to stay complacent despite reports that the Abu Sayyaf, led by Khadaffi Janjalani, has been flushed out the mountains as there are still remnants of the group who may resurface anytime. — With Jaime Laude, AFP