The attack came days after a predominantly Muslim area in the region voted “yes” in a referendum for greater autonomy. At least 27 people were killed with scores more injured, local officials said.Colonel Gerry Besana, spokesman of the military’s Western Mindanao Command, said the first blast killed two civilians and wounded 20 other churchgoers inside the Jolo Cathedral called Cathedral of Our Lady of Mount Carmel in Sulu province.
Mr Besana said the second explosive device was detonated as the soldiers responded to the initial attack inside the church, leaving 15 other members of the security forces wounded.
The government’s plan to create a self-administered area for the Muslim-dominated parts of Mindanao was backed by 85 percent of voters in a referendum last Monday, paving the way for a three-year transition towards elections for a legislature that will choose an executive.
The country’s national police chief Oscar Albayalde said at least 27 people died, including five troops and three civilians.
Jolo island has long been troubled by the presence of Abu Sayyaf militants, who are blacklisted by the United States and the Philippines as a terrorist organisation because of bombings, kidnappings and beheadings.
No one immediately claimed responsibility for the attack.
There are terrorist factions in the region, aside from the small but brutal Abu Sayyaf group, who align themselves with the Islamic State group, which has also carried out assaults, including ransom kidnappings and beheadings.
Abu Sayyaf militants are still holding at least five hostages — a Dutch national, two Malaysians, an Indonesian and a Filipino — in their jungle bases mostly near Sulu’s Patikul town, not far from Jolo.
According to unofficial reports, casualties included both troops and civilians.
Defense Secretary Delfin Lorenzana in a statement: “I have directed our troops to heighten their alert level, secure all places of worships and public places at once, and initiate pro-active security measures to thwart hostile plans.”
Photos on social media showed debris and bodies lying on a busy street outside the cathedral as frightened churchgoers scrambled to get to safety.
Rappler reported local police as saying: “The casualties were immediately evacuated. AFP, PNP (Armed Forces of the Philippines, Philippine National Police) personnel are securing the area.”
They said two improvised explosive devices (IEDs) were used to bomb the cathedral.
Last week’s referendum came at a critical time for the Philippines, which hopes to end decades of separatist conflict in Mindanao that experts say has given rise to extremism.
That has stoked fears that foreign radicals will gravitate to Mindanao to capitalise on porous borders, jungles and mountains, and an abundance of arms.