By Philip Pullella and Dave Sherwood
SANTIAGO (Reuters) - Pope Francis expressed "pain and shame" on Tuesday over a sexual abuse scandal in the Roman Catholic Church in Chile, seeking forgiveness for a crisis that has scarred its credibility and left many faithful skeptical of reform.
Francis, on a trip that will also take in Peru, spoke after at least eight Catholic churches were attacked in Chile in the past week.
Police in riot gear dispersed some 200 demonstrators trying to make their way to a park in Chilean capital Santiago, where the pope - the first Latin American head of the Church - said Mass for some 400,000 people.
Earlier on Tuesday, the Argentine pontiff made his remarks about abuse in a speech at the presidential palace, La Moneda.
"Here I feel bound to express my pain and shame at the irreparable damage caused to children by some ministers of the Church," he said, drawing sustained applause, including from President Michelle Bachelet and diplomats.
"I am one with my brother bishops, for it is right to ask for 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.
Catholics have been upset with Francis' appointment in 2015 of Bishop Juan Barros to head the small diocese of Osorno in south-central Chile.
Barros, who attended Tuesday's Mass, has been accused of protecting his former mentor, Father Fernando Karadima, who was found guilty in a Vatican investigation in 2011 of abusing teenage boys over many years. Karadima has denied the allegations and Barros said he was unaware of any wrongdoing.
"There have been many lies told about my situation," he told Reuters after the Mass.
But, along with growing secularization, the scandal has hurt the standing of a Church that defended human rights during the 1973-1990 dictatorship of Augusto Pinochet.
A poll by Santiago-based thinktank Latinobarometro this month showed that the number of Chileans calling themselves Catholics fell to 45 percent last year, from 74 percent in 1995.
Francis returned to the theme of abuse on Tuesday evening in an address to priests and nuns in Santiago's cathedral. He spoke of "this great and painful evil" which had led victims and their families to "see the trust they had placed in the Church's ministers betrayed."
But he said he also understood the pain of priests and nuns who had nothing to do with abuse and had been unfairly tainted, including being "insulted in the metro or walking on the street."
Hours after the pope arrived in Chile on Monday, two small wooden churches were burned to the ground near Temuco, where Francis is due to visit on Wednesday.
The indigenous Mapuche in the area accuse the state and private companies of taking their ancestral lands. The Mapuche say the pope's ceremony will be held on seized land.
A church in the capital was attacked during the night, causing minor damage. Vandals burned Chilean and Vatican flags at the site and tossed pamphlets with threats against the pope.
At one attack which involved a homemade bomb, a pamphlet was left that read: "Pope Francis, the next bomb will be in your robe."
Graffiti scrawled on one Santiago church read: "Burn the pope."
About 10 blocks from Tuesday's Mass, riot police clashed with people protesting against the sexual abuse scandal and the $17 million cost of the papal visit. "Complicit Pedophiles," read one of the banners.
But the welcome most Chileans have given Francis has been warm, with tens of thousands lining the streets.
At his speech in La Moneda, which Pinochet's forces bombed in September 1973 while democratically-elected President Salvador Allende was inside, Francis said the country had "faced moments of turmoil, at times painful." He praised Chile's consolidation of democracy but said more had to be done to help the unemployed and indigenous.
In the afternoon, Francis made an emotional visit to the San Joaquin prison for women.
The women, many of whose children live in the prison with them, cheered when the pope told them that their dignity could never be taken away from them.
"Society has an obligation to reintegrate each one of you," said the pope, who was clearly moved by stories the women told him of prison life.
(Additional reporting by Felipe Iturrieta; Editing by Frances Kerry and Rosalba O'Brien)