At least 20 people have been killed and 81 injured after two bombs exploded at a Catholic cathedral in the Philippines.

The first bomb went off in or near the church in Jolo during Sunday mass.

This was followed by a second blast outside the building as government forces responded to the attack.

Image: The authorities have vowed to bring those responsible to justice

The explosions tore away the entrance to the cathedral and ripped through the main hall, shredding pews.

Images from the scene showed debris and bodies lying on the street outside the Cathedral of Our Lady of Mount Carmel, which has been targeted by bombs in the past.


Troops in armoured vehicles sealed off the main road leading to the church, as the wounded were evacuated.

Some of those injured were airlifted to nearby Zamboanga city.

Image: The explosions tore through the cathedral, shredding pews

The dead included 15 civilians and five soldiers, according to the authorities, while among the wounded there were 14 soldiers, two police and 61 civilians.

The number of those killed is lower than reported earlier after police issued a correction due to double counting.

Islamic State claimed responsibility.

Defence secretary Delfin Lorenzana said: "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.

"We will use the full force of the law to bring to justice the perpetrators behind this incident."

Image: The area has long been troubled by militants

The office of President Rodrigo Duterte in Manila said in a statement: "We will pursue to the ends of the earth the ruthless perpetrators behind this dastardly crime until every killer is brought to justice and put behind bars. The law will give them no mercy."

Jolo island, in the south of the Philippines, has long been troubled by Abu Sayyaf militants, who are blacklisted by the US and the Philippines as a terrorist group due to years of bombings, kidnappings and beheadings.

A Catholic bishop, Benjamin de Jesus, was gunned down by suspected militants outside the cathedral in 1997.

Regional military spokesman Lieutenant Colonel Gerry Besana said: "The motive is surely... terrorism. These are people who do not want peace."

Image: Casualties included soldiers and civilians

The attack came nearly a week after a referendum in which voters backed a new Muslim-majority autonomous region in the south of the largely Roman Catholic nation, where the island of Jolo is located.

The move is aimed at ending nearly five decades of a separatist insurgency, which has left 150,000 people dead.

While most Muslim areas supported the deal, voters in Sulu province, where Jolo is located, rejected it.

As well as the Abu Sayyaf group, which is not part of any peace process, the province is home to a rival rebel faction that is opposed to the autonomy move.