MANILA, Philippines -- Suspected Moro Islamic Liberation Front (MILF) rebels attacked an Army base in the southern province of Shariff Kabunsuan before dawn on Wednesday, damaging a toilet, but leaving no casualties, officials said.

At around 2:15 a.m., the MILF fired rocket-propelled grenades at Camp Iranun, the headquarters of the 603rd Brigade in Bonbaran village, Tugaig town, said Army spokesman Lieutenant Colonel Romeo Brawner.

Then, at around 5 a.m., the rebels fired 81-millimeter mortars at the camp, Brawner said.

The first attack hit a toilet, the rebel barrage accompanied by M16 rifle fire, Brawner said.

The joint Coordinating Committee on the Cessation of Hostilities (CCCH) and international ceasefire monitors are investigating the incident, Armed Forces spokesman Lieutenant Colonel Ernesto Torres Jr. said.

Later Wednesday, at around 6:30 a.m., Army troops clashed with MILF fighters in Sarangani province, leaving a rebel killed.