VATICAN CITY — Pope Francis on Monday used his first meeting with victims of clerical sexual abuse to offer his strongest condemnation of a crisis that has shaken the Roman Catholic Church, comparing priests who abuse minors to “a sacrilegious cult,” while begging forgiveness from victims and pledging to crack down on bishops who fail to protect children.

By meeting with six victims from three countries, Francis was trying to show resolve — and personal empathy — to address an issue on which he has faced criticism in what has otherwise been a popular papacy. While some advocates for victims praised the meeting, others dismissed it as little more than a publicity stunt.

Francis first greeted the six victims — two people each from Ireland, Britain and Germany — on Sunday after they arrived at a Vatican guesthouse. On Monday morning, he led them in a private Mass at a Vatican chapel, where he offered a strongly worded homily condemning an abuse scandal that began to surface decades ago under John Paul II. Francis also met with each victim individually in sessions that, in total, lasted more than three hours.

“Before God and his people, I express my sorrow for the sins and grave crimes of clerical sexual abuse committed against you,” Francis said during his homily, according to a text released by the Vatican. “And I humbly ask forgiveness. 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.”