One person was injured when a grenade exploded near a polling center in Marantao, Lanao del Sur, the military said, an hour before it was to close to end the conduct of the midterm elections on Monday.

Col. Romeo Brawner Jr., commander of the Philippine Army’s 103rd Infantry Brigade, said three persons, including one identified as a member of the Moro Islamic Liberaion Front (MILF), were responsible for the grenade that exploded inside a van at 5 p.m.