The blasts left 20 people killed.

Rita Katz, Director of SITE Intelligence Group, tweeted: "#ISIS, through Amaq &communique, claims deadly bombing on Christian church in #Jolo, stating it was carried out by 2 suicide bombers. One detonated belt at church gate & second in church’s private parking lot where Filipino security forces gathered after first blast."

United Nations Secretary-General António Guterres has condemned the deadly terrorist attack on a church in restive southern Philippines early Sunday, and has called for the perpetrators to be brought to justice

In a statement issued by a UN spokesperson, the Secretary-General expressed his sincere condolences to the families of the victims and wished a speedy recovery to the wounded.

According to media reports, twin bombings ripped through the Jolo Cathedral in the island province of Sulu, which is in the Philippines southern Bangsamoro region.

The attack occurred during Sunday morning services and reportedly killed nearly 20 people and left more than 80 wounded.

“The Secretary-General calls for the perpetrators of these crimes to be swiftly brought to justice,” the statement said, and added that Guterres reiterated the support of the United Nations to the Philippines Government and people in their efforts to fight terrorism and violent extremism, and to carry forward the peace process in Bangsamoro region.

In late July 2018 President Rodrigo Duterte signed new legislation – formally the Organic Law for Bangsamoro in the Autonomous Region in Muslim Mindanao – which granted extra autonomy to Muslim communities living in the Southern Philippines, raising hopes that years of separatist violence involving central Government troops and militants could be brought to an end.

Today’s attack comes days after voters approved the creation of the Bangsamoro Autonomous Region in majority-Muslim areas of southern Philippines.

But reports suggest that voters in Sulu province, where Jolo is located, rejected it.