Speaking on behalf of the Catholic Church, Pope Francis begged six victims of clerical sexual abuse for forgiveness Monday and promised to hold bishops who hid the sex scandals accountable for their "grave sins."

The pontiff prayed with the "victims of abuse from Ireland, Germany and Britain" and invited them to attend an "early-morning private Mass at the Domus Sanctae Marthae," according to NBC News. During the meeting, he called for "reparation" for those who had suffered at the hands of Roman Catholic priests.

He also described the abuse as a "grave sin" that was concealed for "so much time" and "camouflaged with a complicity that cannot be explained."

"I ask for the grace to weep, the grace for the Church to weep and make reparation for her sons and daughters who betrayed their mission, who abused innocent persons," the pope said during a homily at a Mass the victims attended at his Vatican residence.

"I beg your forgiveness, too, for the sins of omission on the part of Church leaders who did not respond adequately to reports of abuse made by family members, as well as by abuse victims themselves," NBC News reported the pope said.

He likened the abuse to a "sacrilegious cult" and express his personal sorrow for the sins of the Church.

"It is like a sacrilegious cult, because these boys and girls had been entrusted to the priestly charism in order to be brought to God," the pontiff added. "Before God and his people, I express my sorrow for the sins and grave crimes of clerical sexual abuse committed against you, and I humbly ask forgiveness," he said in his homily.

After Mass, Francis held private meetings with the victims and felt "very touched" after, said a Vatican spokesman, per the Los Angeles Times. USA Today reports that "the Vatican did not release the names of the victims."

Critics of the church's numerous sex scandals said this isn't enough.

Andrea Tornielli, coordinator of the Vatican Insider, disagrees. "The rules and laws [regarding accountability for sexual abuse] are already in place," he said, USA Today reported. "But the change of mentality the church needs takes more time. That is why a gesture like this [the meetings] is so important because it will contribute to changing that mentality."