A survivor of clerical sex abuse has resigned from a panel established by Pope Francis to address the issue, saying Vatican officials mounted "shameful" resistance to its work.
Marie Collins was the only remaining panel member abused by a cleric.
She said the commission had suffered constant setbacks, "despite the Holy Father approving all its recommendations".
Pope Francis set up the panel in March 2014.
It was seen as an attempt to address the bitter and long-standing scourge of child abuse which has dogged the Catholic Church.
In her resignation letter, Ms Collins said she believed the pontiff had acted sincerely when he appointed the commission to advise on keeping children safe.
However, she condemned the lack of co-operation by those dealing with cases of abuse.
The Pope himself has been criticised for reducing the punishments given to priests guilty of child abuse.
The Vatican said Pope Francis had accepted her resignation "with deep appreciation for her work on behalf of the victims/survivors of clergy abuse".
Cardinal Sean O'Malley of Boston, the head of the commission, said Ms Collins' concerns would be examined at a meeting next month.
Ms Collins, who is Irish, is the second abuse survivor to leave the panel, known as the Pontifical Commission for the Protection of Minors.
Briton Peter Saunders departed in 2016 after quarrelling with other members about how to handle serial abuse allegations against an Italian priest.
Mr Saunders said he felt betrayed by the Pope and felt he had been tricked into backing up a "smoke and mirrors" exercise.