Suspected Muslim guerrillas detonated a bomb near a Roman Catholic cathedral in the southern Philippines on Sunday, killing at least five people and wounding 46.
Pope Benedict XVI condemned the attack.
The bomb exploded outside the Immaculate Conception cathedral in Cotabato city as churchgoers were attending Mass.
Two people were killed instantly in the attack and three others, including a militiaman, later died in hospitals, military officials said.
Among the wounded were six soldiers and militiamen who were in an army van that passed by the cathedral when the device, fashioned from a mortar round, exploded, Cotabato city Mayor Muslimin Sema said.
The improvised explosive, which was set off remotely by mobile phone, was hidden near a row of food stalls selling roasted pig, Maj Gen Alfredo Cayton said.
Police arrested one man seen using a phone during the explosion. He was carrying three identification cards with different names, Sema said.
Cathedral guard Nestor Luna said shrapnel flew in all directions, inflicting wounds on his head, arms and feet.
"I wanted to help the wounded, but I felt dizzy and saw my white uniform soaked in blood. Somebody helped me walk away," Luna told The Associated Press by telephone from the Cotabato Regional and Medical Center.