Three village security officers have been killed in a shooting in the southern Philippines, as Filipinos vote to elect a new president.

Police and military officials said Monday’s attack happened in Buluan town in Maguindanao province, about 1000 kilometres south of the capital Manila, 90 minutes after polling precincts opened.

The victims were security officers assigned to help secure an elementary school used as a voting centre in the town, a military report said.

Colonel Cristo Lagyup, a regional police spokesman, said no suspects have been identified in the shooting.

“Voting is continuing in the area,” he said.

Police officers and soldiers had been placed on high alert for the elections, which are traditionally marred by violence and allegations of fraud.

The two front-runners in the election are Ferdinand Marcos Jr, the son of the country’s former dictator of the same name, and the current vice president Leni Robredo.