(CNN) -- Pope Benedict XVI said Saturday he is "truly sorry" for the abuse suffered by victims at the hands of Catholic priests in Ireland.

The pope directly addressed the church abuse crisis that has rocked the Irish Catholic Church in an 18-page letter, which was made public Saturday. It is expected to be read in churches across Ireland on Sunday.

"I have been deeply disturbed by the information which has come to light regarding the abuse of children and vulnerable young people by members of the church in Ireland, particularly by priests and religious," the pope wrote.

Read Pope Benedict XVI's letter in full (pdf)

"I can only share in the dismay and the sense of betrayal that so many of you have experienced on learning of these sinful and criminal acts and the way church authorities in Ireland have dealt with them."

The deeply Catholic country has been badly shaken by a government-backed report that found the Archdiocese of Dublin and other Catholic Church authorities in Ireland covered up child abuse by priests from 1975 to 2004. Child sexual abuse was widespread then, the report found.

Church abuse scandal goes global

The head of the church in Ireland, Cardinal Sean Brady, apologized this week for his role in the church's investigation of an abusive priest in 1975.

Brady's office said he investigated the priest, who was later convicted of dozens of counts of child abuse, and reported his findings to his superiors. But critics say Brady should not have remained silent about what he learned.

"No one imagines that this painful situation will be resolved swiftly," Benedict said in his letter.

Contributing factors to the crisis can include inadequate procedures for determining suitable priesthood candidates, insufficient moral and spiritual formation in seminaries, and "misplaced concern for the reputation of the church and the avoidance of scandal," the pope said. He called for them to be addressed urgently.

The pope acknowledged the crisis has shaken people's faith and even turned many away from the church, saying it has "obscured the light of the Gospel to a degree that not even centuries of persecution succeeded in doing."

Benedict then addressed the victims of abuse and their families, recognizing the tragedies they have been through.

"You have suffered grievously and I am truly sorry," he says. "I know that nothing can undo the wrong you have endured. Your trust has been betrayed and your dignity has been violated. Many of you found that, when you were courageous enough to speak of what happened to you, no one would listen."

According to Father Federico Lombardi, the Vatican spokesman, the pope started thinking about writing the letter last summer after the publication of the Ryan report -- one of three separate reports on sexual and physical abuse by Irish clergy that has come out since 2005.

The Ryan report, published in May 2009, investigated abuse in Catholic-run institutions primarily from 1936 to 1970. Many of the alleged abusers in the 2,600-page report were not priests, but nuns or Catholic lay people.

The pope says he expressed "shame and remorse" and asks the victims not to lose hope.

Scandal shatters faith in Catholic Church

"I know some of you find it difficult even to enter the doors of a church after all that has occurred," he says.

"I pray that, by drawing nearer to Christ and by participating in the life of his church -- a church purified by penance and renewed in pastoral charity -- you will come to rediscover Christ's infinite love for each one of you."

Next in the letter, the pope turned his attention to the priests and religious officials who have abused children. He sharply criticized them and said they must answer to the authorities.

"You betrayed the trust that was placed in you by innocent young people and their parents, and you must answer for it before Almighty God and before properly constituted tribunals," he says. "You have forfeited the esteem of the people of Ireland and brought shame and dishonor upon your confreres."

He added, "Together with the immense harm done to victims, great damage has been done to the church and to the public perception of the priesthood and religious life."

The pope urged guilty priests to "take responsibility" for their sins and "seek to atone personally" for their actions.

"Openly acknowledge your guilt, submit yourselves to the demands of justice, but do not despair of God's mercy," he said.

Lombardi said guilty priests should follow the laws in their own country and cooperate with justice authorities, as well as follow the church's rules. Benedict proposed several concrete steps to address the situation, including asking the Irish faithful to pray for the church for one year, starting at Easter.

But he also announced an apostolic visitation of certain Irish dioceses, seminaries, and congregations. Such visitations are actually Vatican investigations; the church held one in the United States after the clerical sex scandal in 2002.

The letter is specific to Ireland and did not address similar scandals now coming to light in other European countries like Austria and Germany. Lombardi said the pope is aware of the situations in those countries, but did not think it was appropriate to address all of them in Saturday's letter.