THE Islamic State organization claimed responsibility for an attack today during a Catholic Sunday service in the southern Philippines that left at least four people dead and 50 others injured, authorities said.

“Soldiers of the caliphate detonated an explosive device among a large gathering of Christians in Marawi City,” the jihadist organization said in a statement posted on its Telegram channels.

Earlier Sunday, before the ISIS announcement, Philippine President Ferdinand Marcos Jr. condemned “the senseless and most abominable acts committed by foreign terrorists”. Police and the military have stepped up security in the south of the country and around the capital, Manila.

In Rome, the Pope Francis prayed for the victims during his speech on Sunday and, in a separate text message, appealed to “Christ the prince of peace (may) give to all the strength to turn away from violence and overcome all evil with good.”

Law enforcement operations to bring perpetrators of “terrorist activity” to justice “will continue unabated,” Defense Minister Gilberto Teodoro told a news conference.

There were “strong evidence of a foreign element» in the bombing, Teodoro said, declining to elaborate.