A major UN child rights protection body has asked the Vatican to disclose details of thousands of paedophilia cases involving Catholic clergy.
The Committee on the Rights of the Child (UNCRC) made the request ahead of its hearing with Holy See officials, scheduled for January.
It is the first time the UN has asked for such a wide-ranging appraisal.
After taking office in March, Pope Francis said cracking down on sex abuse was vital for the Church's credibility.
He said the Vatican needed "to act decisively as far as cases of sexual abuse are concerned, promoting, above all, measures to protect minors, help for those who have suffered such violence in the past (and) the necessary procedures against those who are guilty".
His predecessor, Benedict XVI, had promised to rid his Church of the "filth" of clerical sex abuse.
Observers said he went further than ever before in tackling the legacy of abuse, though critics said that was not far enough, accusing him of failing to protect children from paedophile priests.
'Room for optimism'
The UN Convention on the Rights of the Child is a legally-binding instrument which, once signed by member states, commits them to protecting and nurturing the most vulnerable in society.
The Geneva-based UNCRC, which governs the convention, sent a "list of issues" to the Vatican in view of obtaining "detailed information on all cases of child sexual abuse committed by members of the clergy, brothers and nuns or brought to the attention of the Holy See".
The information relates to all cases between November 1995 and January 2014, the UN said.
The questionnaire seeks to establish whether "perpetrators of sexual crimes" were allowed to remain in contact with children and what legal action was taken against them.
The appraisal also asks whether reporting of suspected abuse was mandatory. In addition it includes queries about support for victims, and any incidents where complainants were silenced.
The British National Secular Society said there was "room for optimism that [Pope Francis] will try much harder than his predecessor to address this issue which has caused so much pain, made so much worse by the Church's actions and inactions over decades, if not centuries".
But observers say that although the Convention on the Rights of the Child is legally-binding, the Vatican may be able to refuse this request from the committee.
The appraisal comes ahead of Vatican officials due to appear before the UNCRC in January to be questioned over clerical paedophilia as well as other issues.
The Vatican recently set up new guidelines to prevent future abuse, stressing that it would help victims, forewarn minors, train future clergy, rehabilitate abusers and work alongside civil authorities.