SANTIAGO, Chile — Pope Francis begged for forgiveness Tuesday for the “irreparable damage” done to children who were raped and molested by priests, opening his visit to Chile by diving head-first into a scandal that has greatly hurt the Catholic Church’s credibility here and cast a cloud over his visit.

Francis faced controversy on another front as well: Overnight three more Catholic churches were torched, including one burned to the ground in the southern Araucania region where Francis will visit on Wednesday to meet with Chile’s indigenous peoples. While not causing any injuries, the nine church firebombings in the past few days have marked an unprecedented level of protest against history’s first Latin American pope on his home turf.

In Santiago, though, an estimated 400,000 jubilant Chileans turned out in droves for his first public Mass, a massive gathering in the capital’s O’Higgins park where St. John Paul II celebrated Mass three decades ago. Francis took a long, looping ride in his popemobile through the grounds to greet well-wishers, some of whom had camped out overnight to secure a spot.

In his first event of the day, Francis met privately with Chilean President Michelle Bachelet and addressed lawmakers, judges and other authorities. They interrupted him with applause when he said he felt “bound to express my pain and shame” that some of Chile’s pastors had sexually abused children in their care.

“I am one with my brother bishops, for it is right to ask forgiveness and make every effort to support the victims, even as we commit ourselves to ensuring that such things do not happen again,” he said.

Francis didn’t refer by name to Chile’s most notorious pedophile priest, the Rev. Fernando Karadima, who was sanctioned in 2011 by the Vatican to a lifetime of “penance and prayer” for sexually molesting minors.