Washington: Pope Francis on Wednesday told U.S. Roman Catholic bishops that crimes of sexual abuse of minors by clergy should never be repeated, acknowledging the damage caused by years of scandal in the US Catholic Church.

In the remarks, delivered at Saint Matthews Cathedral in Washington on the first full day of his visit to the United States, the pope did not utter the words "sexual abuse" but referred to the scandal by talking about "difficult moments" and providing help for victims.

"I know how much the pain of recent years has weighed upon you, and I have supported your generous commitment to bring healing to victims ... and to work to ensure that such crimes will never be repeated," Francis told the bishops, who applauded.

Wounds from the scandal, which saw priests who abused children moved from parish to parish instead of being defrocked, are still festering and draining church finances.

The U.S. church has already been dealt a heavy financial blow by settlement payments and other costs totalling around $3 billion, which has forced it to sell off assets and cut costs.

The pontiff has vowed to root out "the scourge" of sex abuse from the Roman Catholic Church, and last June created a Vatican tribunal to judge clergy accused of covering up or failing to prevent sexual abuse of minors.

Victims` groups say the church has not done enough.

On Wednesday, David Clohessy, head of the Survivors Network of those Abused by Priests, who himself was sexually assaulted by a priest as a child, said he was unimpressed by Francis` words.

"It`s dreadfully disappointing. Bishops have been cowardly, not courageous, and still are," Clohessy said. "What grudging, belated steps they have taken have been forced on them by the most courageous people in this crisis, abuse victims and their families."

Clohessy said Francis "refuses to even be honest about what this crisis is. These are not quote-unquote `difficult moments,` this is a centuries-old, incredibly unhealthy and self-surviving pattern of secrecy and recklessness," Clohessy said in a phone interview after the pope`s remarks.

During his six days in the United States, the pope may meet privately with victims of sexual abuse. The Vatican has said an eventual meeting would be announced after it takes place in order to protect the privacy of the victims.