Pope Francis has said he feels "pain and shame" over a sex abuse scandal which has rocked the Catholic Church in Chile.
The Pope also asked the victims of sexual abuse committed by priests for forgiveness.
He made the remarks during his first official address in Chile.
The Pope had been criticised in Chile for his decision to ordain a bishop who is accused of covering up sexual abuse committed by a priest.
Pope Francis has said in the past that dealing with abuse is vital for the Church's credibility, and that "sanctions" must be imposed against perpetrators.
But critics in Chile say he failed to respond to their request to review the appointment of Juan Barros as bishop of Osorno.
Parishioners in the southern Chilean city say Bishop Barros used his position in the Catholic Church to try to block an investigation into the actions of his mentor, Catholic priest Fernando Karadima.
The case of Fr Karadima, an influential priest who was found guilty by the Vatican of sexually abusing young boys and ordered to do penance, shook the Catholic Church in Chile.
Pope Francis said on Tuesday that he was sorry for the "irreparable harm" caused to the victims of sexual abuse by Church ministers.
On Monday, activists fighting for the rights of sexual abuse victims gathered in Santiago for a conference.
They launched an organisation called Ending Clerical Abuse which "seeks to stop child sexual abuse by the clergy" worldwide.
Speaking on the sidelines of the conference, one of the activists, Juan Carlos Cruz, told the BBC that "the time for saying sorry and forgiving is over".
"[Saying sorry] is not sufficient for a survivor. What we want is for the Pope to take action."
"There are concrete things that he can do, like removing priests who have been accused and sentenced by the Chilean justice system or canon law and bishops who have covered up [sexual abuse]," he says.
Vatican spokesman Greg Burke has said Pope Francis might meet victims of sexual abuse in private, as he has on past trips, but there has been no official confirmation of such a meeting.
Under Pope Francis, a Vatican committee has been set up to fight sexual abuse and help victims but Chilean victims of clerical sex abuse say more transparency is needed.