The Philippines' military says troops on a jungle patrol hit a trip wire planted by Muslim militants. It wounded 22 soldiers, five of them critically.
The bomb exploded on southern Basilan Island on Tuesday near a camp of Abu Sayyaf rebels that troops captured during fighting last month.
Military commander Col. Ricardo Visaya says the soldiers were clearing the camp of leftover explosives when they walked into the trip wire hidden in thick vegetation.
Several hundred Abu Sayyaf fighters in the southern Philippines have been blamed for bomb attacks and ransom kidnappings despite battlefield setbacks dealt by U.S.-trained Philippine forces.
The guerrillas operate from jungle camps and hold several foreigners hostage.