Francis presided over his weekly general audience in St Peter's Square and spoke about his weekend trip to Ireland, where the abuse scandal has devastated the Catholic Church's credibility.
The final day of the trip was overshadowed by release of a document from a retired Holy See diplomat accusing Vatican authorities, including Francis, of covering up for ex-Cardinal Theodore McCarrick - despite knowing for years that he regularly slept with religious scholars.
The author of the document - retired Vatican ambassador to the US Archbishop Carlo Maria Vigano - said Francis should resign for his complicity in the McCarrick scandal, which has implicated US and Vatican church leaders over a period of two decades.
Francis referred to the Irish culture of cover-up, but he omitted from his remarks a line in his prepared text noting how he had prayed in Ireland for the Virgin Mary to intervene to give the church strength to "firmly pursue truth and justice" to help victims heal.
US bishops have called for an independent investigation to find out who knew about McCarrick's abuse and when, and how he was able to rise through the ranks even though it was an open secret that he regularly invited seminarians to his New Jersey beach house and into his bed.
Francis last month removed McCarrick as a cardinal and ordered him to live a lifetime of penance and prayer after a US church investigation determined that an allegation he groped a teenage altar boy in the 1970s was credible.
Mr Vigano's 11-page letter alleges that Francis knew of McCarrick's attitude to seminarians starting in 2013, but rehabilitated him from sanctions that Pope Benedict XVI had allegedly imposed on him in 2009 or 2010.
There is ample evidence, however, that the Vatican under Benedict and St John Paul II also covered up the information, and that any reported sanctions Benedict imposed were never enforced since McCarrick travelled widely for the church during those years, including to Rome to meet with Benedict and celebrate Mass with other US bishops at the tomb of St Peter.
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