VATICAN CITY | The bishop of the Diocese of Sioux City on Monday said he supports Pope Francis' desire to seek forgiveness from Catholics who were sexually abused by members of the clergy.

Pope Francis begged forgiveness in his first meeting with Catholics who were victims of abuse, and went further than any of his predecessors by vowing to hold bishops accountable for their handling of pedophile priests.

"I whole-heartedly support Pope Francis’ mission that we as bishops must carry out our ministry with 'the utmost care' to protect our young people," said Bishop R. Walker Nickless.

Abuse victims and their advocates have long demanded that higher-ups be made to answer for the decades-long cover-ups of rape and molestation of youngsters in a scandal that has rocked the church and dismayed its worldwide flock of 1.2 billion.

The pope celebrated a private Mass on Sunday with six victims — two each from Ireland, Britain and Germany — at his Vatican residence, and spent the rest of the morning listening to their accounts, one on one.

"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," Francis said on Monday.

"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," the pope said.

Nickless said the pontiff's actions mark a "small, important step" in helping victims heal from the pain of priest sexual abuse.

"I'm personally moved by these six victims' willingness to meet with Pope Francis and open the door to forgiveness," Nickless said.

"Their amazing courage to speak up at this terrible injustice that was put upon them should inspire us all," he said.

In delivering his homily in his native Spanish, Pope Francis said, "All bishops must carry out their pastoral ministry with utmost care in order to help foster the protection of minors, and they will be held accountable."

Nickless, who was named bishop of the Diocese of Sioux City in November 2005, oversees more than 100 parishes and 95,000 Catholics in Northwest Iowa. There are eight parishes in Sioux City.

Nickless said it is imperative that young Catholics are protected from the potential for abuse.

"All of us who serve the Church need to keep their safety at the forefront of everything we do," Nickless said.

The U.S.-based victims group SNAP, or the Survivors Network of those Abused by Priests, reacted skeptically to the pontiff's remarks.

"We are glad the pope promises to 'hold accountable' Catholic officials who conceal abuse," SNAP Director David Clohessy said in statement. "But he hasn't done it yet, not in Rome, nor in Buenos Aires. Saying and doing are different things. The first is easy, the second is hard."

Anne Barrett Doyle, a director of another victims advocacy group, BishopAccountability.org, said the pope's meeting with the three men and three women was still a positive step.

"The pope made a significant and historic promise to discipline bishops who fail to respond adequately to child sexual abuse," she said.

-- The Associated Press contributed to this report.