COTABATO CITY, Philippines—(UPDATE) A militiaman was killed when an improvised explosive device went off Monday morning near a detachment of the Civilian Armed Forces Geographical Unit (Cafgu) in Upi, Maguindanao.

The lone fatality was identified as Erol Roberts, said Superintendent Danilo Bacas, spokesman of Autonomous Region of Muslim Mindanao.

Mayor Ramon Piang said the explosion occurred at about 8 a.m. beside a Cafgu detachment in the village of Kibleg, some 10 kilometers from the town proper.

Piang said civilian volunteers found the explosive placed inside a bag and left unattended near the detachment and alerted the lawmen.

A militiaman was checking the explosive when it went off.

The victim was rushed to the Datu Blah Sinsuat district hospital where he was pronounced dead due to shrapnel wounds.

Lieutenant Colonel Jonathan Ponce, 6th Infantry Division spokesman, said Army bomb experts have started investigating the attack.

Quoting reports from the 6th Infantry Battalion based in Upi, Mayor Piang said the explosive was triggered by battery-operated blasting mechanism.

No one has claimed responsibility for the attack.