Successive blasts targeted the mosque inside Camp Kasim on the island of Jolo early Friday evening — an initial grenade attack followed by a bomb explosion less than 10 minutes later that was intended to target police who rushed to the scene, local authorities said.
“It seems the [first] explosion was set up to draw responders as the target,” the provincial police chief Senior Superintendent Abraham Orbita told reporters.
Rosalyn Aya-ay, a shopkeeper and policeman’s wife, said she found her husband sprawled on the ground after the first explosion and took him to the camp hospital, though he was not seriously injured.
“When I returned I found my two daughters wounded by the second blast. I was scared and I had a hard time finding an ambulance to carry them,” she told AFP.
No group has claimed responsibility for the attack, which occurred inside the sprawling police headquarters in the provincial capital of Jolo, a mainly Muslim island in the south of the predominantly Catholic Asian nation.
It was the second bomb attack on Camp Kasim since 2010, when a Christmas Day blast wounded six people worshipping at a Catholic church in another section of the facility.
Jolo is a known stronghold of Abu Sayyaf, a small group of a few hundred Islamic militants founded in the 1990s with seed money from Al Qaeda.
Police investigators combed through the scene of the blast Saturday, which was about 10 metres (33 feet) from a guarded entry gate, but would not say how the attackers had smuggled the explosives into the camp, an AFP photographer on the scene said.
The families of policemen assigned to the camp also live inside the facility.
The Abu Sayyaf gained international notoriety for some of the worst terror attacks in Philippine history including bombings and kidnappings of Christians and foreigners for ransom.
Filipino security forces have for more than a decade received counter-terrorism training assistance from the United States, which sent military advisers on short-term deployments to Jolo and other areas.
However the Philippines has struggled to contain the group, whose leader last year pledged allegiance to Islamic State militants fighting in Syria and Iraq.