The bomb, made of four 81 mm mortar rounds and detonated by cellphone, went off on a parked motorcycle in front of a gun store in Cotabato City on Tuesday, officials said.

A security guard on his way to work was killed while shrapnel and glass splinters from shattered window panes wounded 12 others, including a 7-year-old girl, Cotabato city police chief Superintendent Roberto Badian said.

No one has claimed responsibility for the attack but army ordnance experts reported that the bomb design closely resembled those used by suspected Muslim guerrillas and militants belonging to the Southeast Asian terrorist network Jemaah Islamiyah in at least three recent attacks, said regional army spokesman Col. Prudencio Asto.

Police also have no suspects but are looking into reports that the owner of the gun store was involved in a land dispute, said police regional operations chief Felicisimo Khu Jr.

AP