A bombing at a Roman Catholic cathedral in the Philippines on Sunday killed 20 people and left 111 injured, according to the Associated Press. Two bombs exploded within minutes during mass at Cathedral of Our Lady of Mount Carmel in Jolo, which is located on an island known as a militant hotspot. The first blast forced many wounded churchgoers to flee the building. Philippine troops and police who were outside the church were on their way inside when the second bomb exploded. Military officials were checking to see whether the second bomb was on a parked motorcycle. Abu Sayyaf militants, blacklisted by the Philippines and United States as a “terrorist organization,” have operated on Jolo for years, carrying out beheadings, kidnappings and bombings, per the AP. Catholic Bishop Benjamin de Jesus was shot by alleged Abu Sayyaf members outside the cathedral some 20 years ago.