More than 100 wounded in twin-bomb attack during church service in Jolo.Two bombs minutes apart tore through a Roman Catholic cathedral on a southern Philippine island where Muslim militants are active, killing at least 20 people and wounding 111 others during a Sunday Mass, officials said.   Witnesses said the first blast inside the Jolo cathedral in the provincial capital sent churchgoers, some of them wounded, stampeding out of the main door. Army troops and police posted outside were rushing in when the second bomb went off about one minute later near the main entrance, causing more deaths and injuries. The military was checking a report that the second explosive device may have been attached to a parked motorcycle. The initial explosion scattered the wooden pews inside the main hall and blasted window glass panels, and the second bomb hurled human remains and debris across a town square fronting the Cathedral of Our Lady of Mount Carmel, witnesses said. Cellphone service was cut off in the first hours after the attack. The witnesses who spoke to The Associated Press refused to give their names or were busy at the scene of the blasts. Police said at least 20 people died and 111 were wounded, correcting an earlier toll due to double counting. The fatalities included 15 civilians and five troops. Among the wounded were 17 troops, two police, two coast guard responders and 90 civilians. Troops in armoured carriers sealed off the main road leading to the church while vehicles transported the dead and wounded to the town hospital. Some casualties were evacuated by air to nearby Zamboanga city. Troops on heightened alert"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," said Defence Secretary Delfin Lorenzana 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," the office of President Rodrigo Duterte said in Manila. It said that "the enemies of the state boldly challenged the government's capability to secure the safety of citizens in that region. The [Armed Forces of the Philippines] will rise to the challenge and crush these godless criminals." Jolo island has long been troubled by the presence of Abu Sayyaf militants, who are blacklisted by the United States and the Philippines as a terrorist organization because of years of bombings, kidnappings and beheadings. A Catholic bishop, Benjamin de Jesus, was gunned down by suspected militants outside the cathedral in 1997. No one has immediately claimed responsibility for the latest attack. AFP.