MANILA, Philippines (AP) — Suspected Muslim militants ambushed a truckload of rubber plantation laborers in the restive southern Philippines on Wednesday, killing six and wounding 22, following a day of fighting in which eight soldiers were wounded, officials said.

The army commander on Basilan Island, the militants’ stronghold, blamed al-Qaida-linked Abu Sayyaf rebels for the violence, which came despite efforts by U.S.-trained Philippine forces to put an end to decades of bombings and ransom kidnappings by the extremists in the predominantly Christian nation.