Pope Francis told reporters Sunday that he "won't say a word" about claims by a former Vatican ambassador to the U.S. that the pontiff had rehabilitated the former archbishop of Washington, Theodore McCarrick, despite being made aware of sexual misconduct claims against him.

In an 11-page memo made public Saturday evening, Archbishop Carlo Maria Viganò called on Francis to resign over his handling of the McCarrick matter. The most eye-opening claim by Viganò was that Pope Benedict XVI had sanctioned McCarrick in 2009 or 2010 -- in essence prohibiting him from public ministry and ordering him to carry out a life of prayer and penance -- only for Francis to re-instate him, "cover" for him and advance him to the role of a "trusted counselor."

Returning to Rome from a two-day visit to Ireland, Francis said that he had read Viganò's memo and thought it "speaks for itself."

Francis accepted McCarrick's resignation as cardinal last month, after a U.S. church investigation determined that an accusation he had sexually abused a minor was credible.

FORMER VATICAN DIPLOMAT CALLS FOR POPE FRANCIS TO RESIGN, SAYS HE IGNORED SEX ABUSE ALLEGATIONS

Since then, another man has come forward to say McCarrick began molesting him starting when he was 11, and several former seminarians have said McCarrick abused and harassed them when they were in seminary. The accusations have created a crisis of confidence in the U.S. and Vatican hierarchy, because it was apparently an open secret that McCarrick regularly invited seminarians to his New Jersey beach house, and into his bed.

Coupled with the devastating allegations of sex abuse and cover-up in a recent Pennsylvania grand jury report — which found that 300 priests had abused more than 1,000 children over 70 years in six dioceses — the scandal has led to calls for heads to roll and for a full Vatican investigation into who knew what and when about McCarrick.

Viganò, the papal ambassador -- or nuncio -- to Washington between 2011 and 2016, identified the Vatican cardinals and U.S. archbishops who were informed about the McCarrick affair by name, an unthinkable expose for a Vatican diplomat to make. He said documents backing up his version of events are in Vatican archives.

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Pope Francis greets Cardinal Theodore McCarrick in this undated photo.

He said Francis asked him about McCarrick when they met on June 23, 2013, at the Vatican's Santa Marta hotel where the pope lives, three months after Francis was elected pope.

Viganò wrote that he told Francis: "Holy Father, I don't know if you know Cardinal McCarrick, but if you ask the Congregation of Bishops, there is a dossier this thick about him. He corrupted generations of seminarians and priests, and Pope Benedict ordered him to withdraw to a life of prayer and penance."

Soon thereafter, Viganò wrote, he was surprised to find that McCarrick had started traveling on missions on behalf of the church, including to China. McCarrick was also one of the Vatican's intermediaries in the U.S.-Cuba talks in 2014.

Viganò's claim that McCarrick had been ordered by Benedict to stay out of public ministry and retire to a lifetime of prayer is somewhat disputed, given that McCarrick enjoyed a fairly public retirement. Viganò provides no evidence that such sanctions were imposed by Benedict, saying only that he was told they were.

Viganò, however, also has had his own problems with allegations of cover-up, and he and Francis had a major dust-up during Francis' 2015 visit to the U.S., which Viganò organized.

In that incident, a leading U.S. opponent of gay marriage, Kim Davis, was among those invited to meet with the pope at Viganò's Washington residence. Francis was so enraged that Davis' supporters had leaked word of the meeting that the Vatican subsequently insisted he only held one private audience while there: with one of his former students, a gay man and his partner.

The cover-up accusation, which Viganò denied, concerned allegations that he tried to quash an investigation into the former archbishop of St. Paul-Minneapolis, Minn., John Nienstedt, who was accused of misconduct with adult seminarians.

In 2016, the National Catholic Reporter said Viganò allegedly ordered the investigation wrapped up and a piece of evidence destroyed. The report cited a 2014 memo from a diocesan official that was unsealed following the conclusion of a criminal investigation into the archdiocese. No charges were filed.

In a statement provided to the Associated Press Sunday about the Nienstedt case, Viganò said a Vatican investigation of the allegation found no wrongdoing on his part.

He said the allegation that he destroyed evidence was false and that his efforts to have the archdiocese correct the record have been met with silence.

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Archbishop Carla Maria Viganò.

Nienstedt was forced to resign in 2015 over complaints about his handling of sex abuse cases.

Viganò's name also made headlines during the 2012 "Vatileaks" scandal, when some of his letters were published. In them, he begged not to be transferred to the Vatican embassy in Washington from the administration of the Vatican City State.

He claimed he was being punished for having exposed corruption in the Vatican. The letters showed a clash with Benedict's No. 2, Cardinal Tarcisio Bertone, who is also a target of his McCarrick missive.

The document's authenticity was confirmed to The Associated Press by an Italian journalist, Marco Tosatti, who said he was with Viganò when the archbishop wrote it Wednesday.

"He was very emotional and upset at the end the effort," Tosatti told AP, adding that Viganò left Tosatti's home afterward without saying where he was going.

Fox News' Hollie McKay and The Associated Press contributed to this report.