ISIS has claimed responsibility for the bombing of a Roman Catholic cathedral in the Philippines that killed at least 20 people and injured at least 111 on Sunday, NPR reports. The group claimed its alleged role in the attack via its Amaq news agency just hours after two bombs struck the Cathedral of Our Lady of Mount Carmel in Jolo, an island known for housing Islamist militants, during Sunday mass. The first bomb reportedly sent churchgoers fleeing from the temple; the second struck just as first responders were attempting to enter the building. “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 office of President Rodrigo Duterte said. “The law will give them no mercy.” The Associated Press notes that militants from Abu Sayyaf, a group affiliated with the Islamic State that is known for beheadings, kidnappings and bombings, have been active on Jolo for years.