The pontiff faces criticism in a bombshell letter published as he begs for forgiveness at the end of his historic Ireland visit.
A former Vatican official has claimed Pope Francis had known about allegations of sex abuse against a prominent cardinal in the US for years.
As the pontiff ended his historic two-day visit to Ireland, Archbishop Carlo Maria Vigano called on him to quit over his response to the global scandal still enveloping the Church.
Francis used a speech at Mass in Phoenix Park in Dublin on Sunday to “ask forgiveness” for abuses committed by “members with roles of responsibility in the Church”, which allegedly includes American Cardinal Theodore McCarrick.
The 88-year-old resigned last month over claims of sexual abuse against a 16-year-old boy. Francis accepted McCarrick’s resignation as cardinal last month, after an internal US investigation found that an accusation he had sexually abused a minor was credible.
Archbishop Vigano has said he warned Francis about the allegations shortly after he became Pope in 2013.
In an 11-page statement, the archbishop compared cover-ups of abuse within the Church to “a conspiracy of silence not so dissimilar from the one that prevails in the Mafia”.
“Pope Francis has repeatedly asked for total transparency in the Church,” Archbishop Vigano, a frequent critic of the Pope, wrote in the letter, which was carried by the National Catholic Register and several other conservative media outlets in the US and Italy.
“In this extremely dramatic moment for the universal Church, he must acknowledge his mistakes and, in keeping with the proclaimed principle of zero tolerance, Pope Francis must be the first to set a good example for cardinals and bishops who covered up McCarrick’s abuses and resign along with all of them,” he said.
The Vatican has not commented on the accusations, which include an assertion that other top officials were warned about McCarrick – one of the highest-ranking figures within the Church – as early as 2006.
Archbishop Vigano – the papal envoy in Washington from 2011 to 2016 – timed the release of the bombshell letter to coincide with the second day of the World Meeting of Families in Ireland.
Francis touched down in Ireland on Saturday morning for what was set to be a highly charged two-day trip – the first papal visit to the country since 1979.
The Catholic Church has been vilified in Ireland after 9,000 reported cases of child abuse by priests and Francis met survivors during his first day in Dublin, during which he reportedly compared the corruption to human excrement.
He also made a speech at Dublin Castle in which he expressed his regret over historical abuse by Catholic priests in the country, and on Sunday he struck much the same tone.
During a morning visit to Knock Shrine, where many Irish Catholics believe the Virgin Mary and other Saints were seen in the late 19th century, Francis described the issue of abuse in Ireland as an “open wound”.
And at Mass at Phoenix Park in the afternoon, the Pope requested a “pardon” for their crimes.
“We ask forgiveness for the abuses in Ireland, abuses of power, of conscience, and sexual abuses perpetrated by members with roles of responsibility in the Church,” he said.
“In a special way, we ask pardon for all the abuses committed in various types of institutions run by males or female religious, and by other members of the Church, and we ask for forgiveness for those cases of exploitation through manual work that so many young women and men were subjected to.
“We ask forgiveness.”
Irish Prime Minister Leo Varadkar – who describes himself as a non-practising Catholic – also attended the Mass.
Ahead of the gathering, he tweeted: “Ireland is a different country to 39 years ago. But this visit has caused us to reflect more deeply on the relationship between Ireland the Church, brought to Ireland centuries ago.”
On Saturday, during his welcome speech at Dublin Castle, Mr Varadkar was unafraid to refer to “dark aspects” of the history of the Church and condemned the abuse as “stains on our state, our society and also the Church”.