Police say a bomb has exploded on a southern Philippine highway as a passenger bus was driving by, wounding two civilians on board and three government militiamen on the road.
Senior Supt Marcelo Pintac says it is not clear if Thursday morning's blast in southern Maguindanao province's Pandag township was targeting the bus or the militiamen guarding a nearby military detachment.
He says the wounded are all in stable condition and their statements are being gathered. Soldiers and police have not yet identified the type of bomb used nor pinpointed motives and suspects.
The volatile province is home to Muslim rebels, extortion gangs and a powerful clan blamed for the 2009 massacre of at least 57 people.