Pope Francis has apologised for remarks he made last week in Chile defending a bishop accused of covering up sexual abuse.
He said he realised his words hurt many, but repeated his belief that Chilean Bishop Juan Barros was innocent.
He was speaking to journalists on board a plane flying back to Rome.
On Thursday, the Pope said that victims who had accused Bishop Barros were committing slander.
The Pope was openly criticised by Cardinal Sean O’Malley of Boston, who said he left victims of sexual abuse committed by priests feeling abandoned.
“I apologise to them if I hurt them without realising it, but it was a wound that I inflicted without meaning to,” said the Pope on Monday, quoted by Reuters news agency. “It pains me very much.”
A rare apology
Analysis by James Reynolds, BBC Rome correspondent
It is unusual for a Pope to apologise for his own words. But he clearly felt that he had to make up for his abrupt dismissal of allegations made by victims of clerical sexual abuse in Chile.
The victims had accused a Chilean Bishop, Juan Barros, of covering up crimes committed by a fellow priest.
During his trip to Chile, the Pope described these accusations as a slander, for which there was not a shred of evidence.
The Pope has now apologised for his choice of words. He said that he understood that by essentially daring victims to bring him proof, it came off as a slap in the face.
However, the Pope continued to insist that an investigation had shown that there was no evidence to support the charges levelled against Bishop Barros.