Rome, Italy (CNN) -- The sexual abuse of children is not just a "heinous crime" but a "grave sin" that offends God and wounds human dignity, Pope Benedict XVI said Tuesday after a two-day meeting with Irish Catholic bishops at the Vatican.
The weakening of faith has also been a "significant contributing factor" in the sexual abuse of minors, the pope said, adding that "current painful situation will not be resolved quickly."
The pope's comments came in a written Vatican statement at the end of the meeting, the largest one yet about the scandal that has rocked the church from Ireland to the Vatican and beyond.
A damning report by an independent Irish commission in November found the Catholic Church in Ireland had covered up the "widespread" abuse of children from 1975 to 2004.
It led to the resignation of four Irish bishops late last year and prompted the pope to say at the time he was "deeply disturbed and distressed" by the report's findings.
A group representing alleged victims of abuse said the pope had not gone far enough.
Victims are "angered his Holiness did not see fit to take the necessary firm action against those in the Irish Church hierarchy who protected pedophiles," said John Kelly, the founder of Irish Survivors of Child Abuse.
The pope "has clearly failed the victims and the Irish people," he added.
Asking the bishops to address the problem "shows lack of vision, especially as it is the Irish bishops who are themselves the problem," Kelly said in the written statement.
There was no discussion at this week's meeting about further resignations, said papal spokesman Father Federico Lombardi.
Those at the meeting "recognized that this grave crisis has led to a breakdown in trust in the church's leadership and has damaged (the church's) witness to the gospel and its moral teaching," the Vatican statement said.
"The bishops spoke frankly of the sense of pain and anger, betrayal, scandal and shame expressed to them on numerous occasions by those who had been abused," it said.
It said "significant measures have now been taken" to ensure the safety of children in the church.
"For his part, the Holy Father observed that the sexual abuse of children and young people is not only a heinous crime, but also a grave sin which offends God and wounds the dignity of the human person created in his image," the statement said.
The pope challenged the bishops to address past problems with "determination and resolve" and to face the current crisis with "honesty and courage."
"The Holy Father also pointed to the more general crisis of faith affecting the church and he linked that to the lack of respect for the human person, and how the weakening of faith has been a significant contributing factor in the phenomenon of the sexual abuse of minors," the statement said.
"He stressed the need for a deeper theological reflection on the whole issue, and called for an improved human, spiritual, academic and pastoral preparation both of candidates for the priesthood and religious life and of those already ordained and professed."
The pope wrote a pastoral letter to Irish Catholics to be issued during Lent, the 40-day period between Ash Wednesday, which happens tomorrow, and Easter, the Vatican said.
"The Holy Father has asked that this Lent be set aside as a time for imploring an outpouring of God's mercy and the holy spirit's gifts of holiness and strength upon the church in Ireland," the statement said.
At a Mass in Rome on Monday before meeting the pope, the Irish Catholic bishops prayed for the victims of the abuse in Ireland, said their spokesman, Martin Long.
One of the bishops said Sunday that the church in Ireland had been badly damaged by the revelations of abuse and cover-up.
"I would admit quite frankly what everybody else knows, shouted from house tops, that the church has been seriously wounded," Bishop Joseph Duffy said in Rome.
"This has done an immense damage to the authority of the church as the mouthpiece of the gospel of Jesus Christ. Of that there is no doubt," he said.
The pope already met in December with senior Irish bishops about the report, produced by the Dublin Archdiocese Commission of Investigation. The Irish government created the commission in 2006 to examine abuse allegations.