Philippine soldiers and investigators are probing the centre of the Catholic cathedral in Jolo where the first bomb went off during mass on Sunday morning, killing at least 20 people.

In one of the deadliest attacks in the southern Philippines in years, a bomb blast at a church killed at least 20 people and injured 112 on Sunday morning, 27 January.

Among the dead are five soldiers who came to the rescue after the first bomb went off inside the Cathedral of Our Lady of Mount Carmel in Jolo, an island near Mindanao, and were hit by a second explosion in the church’s parking lot. Six children were wounded in the first blast in the centre of the church which happened during mass with some 100 people attending, reported the Philippines’ daily Rappler.

The twin bombings took place two days after the Muslim-majority Mindanao region, of which Jolo is a part, voted to become self-governing. However, Sulu province, of which Jolo is the capital, rejected it, said AsiaNews.

The passing of Bangsamoro Organic Law (BOL) in the referendum on Friday, 25 January, raised hopes that it would be a step towards ending almost 50 years of conflict in the region between the Philippines’ army and rebel groups.

The largest rebel group, the Moro Islamic Liberation Front, had been a strong supporter of the referendum and the creation of a separate Bangsamoro authority, but there are other rebel groups who fear they will lose power under the new regime, reported Al Jazeera.

The self-proclaimed Islamic State has claimed responsibility for both attacks according to SITE, a website that monitors extremist networks. The Philippine government, however, has blamed the Abu Sayyaf group, an organisation that has pledged allegiance to IS, saying it was “in retaliation” for the death of one of the group’s leaders last year, reported the Catholic news site UCAN.

On Monday the Philippine National Security Advisor said investigations were ongoing into two groups and six persons in particular, Rappler reported.

The army and the police are on heightened alert, Rappler said. “Christian schools are being secured as they are most likely targets of [further] attacks,” a Christian worker from Jolo told World Watch Monitor.

‘No connection with referendum’

MILF’s chairman, Hadji Murad Ibrahim, told UCAN he did not see a connection between the referendum and the attack.

The BOL “is for peace and it will protect not only the rights of [Muslims] but also non-Bangsamoro people like Christians”, he said.

“We are not dividing people. In fact we are uniting Muslim and Christian people,” he said.

Christians, a minority in the region, have been generally supporting the creation of Bangsamoro but have also expressed their apprehension about possible knock-on effects of living in an independent Muslim-led territory, as World Watch Monitor reported in August.

In 2017 the city of Marawi on Mindanao island was for five months under siege by a rebel group affiliated to Islamic State. The Maute group killed civilians and took hundreds of mainly Christian citizens, including a Catholic priest, hostage. They set fire to buildings including a cathedral and Protestant-run college, and erected the black flags of IS.