Cardinal Theodore McCarrick answers questions at a Senate committee hearing in 2011. (Jahi Chikwendiu/The Washington Post)

A former Vatican ambassador to the United States has alleged in an 11-page letter that Pope Benedict XVI and Pope Francis — among other top Catholic Church officials — had been aware of sexual misconduct allegations against former D.C. archbishop Cardinal Theodore McCar­rick years before he resigned this summer.

The letter from Archbishop Carlo Maria Viganò, who was recalled from his D.C. post in 2016 amid allegations that he’d become embroiled in the conservative American fight against same-sex marriage, was first reported by the National Catholic Register and LifeSite News, two conservative Catholic sites.

The accusations sent a shock wave across the reeling Roman Catholic Church, but the letter offered no proof of its claims, and Viganò on Sunday told The Washington Post that he wouldn’t comment further, beyond confirming that he was the letter’s author.

“Silence and prayer are the only things that are befitting,” he said.

The accusations came as Francis wrapped up one of the most challenged trips of his papacy, where in Ireland he came face to face with the national anger and grief caused by decades of abuse. In a Mass at Dublin’s Phoenix Park, Francis spoke in Spanish and asked for forgiveness for what he called “abuses of power, conscience, and sexual abuse perpetrated by members with roles of responsibility in the church,” according to a Vatican News translation of his remarks.

“We ask forgiveness for some members of the church’s hierarchy who did not take charge of these painful situations and kept quiet,” Francis said.

Speaking to reporters on the papal plane while returning to Rome, Francis declined to address the claims but said the letter “speaks for itself.”

“I read the statement this morning and, sincerely, I must say this to you and anyone interested: Read that statement attentively and make your own judgment,” Francis told reporters, according to the Catholic News Service.

Asked when he first learned of allegations about McCarrick, Francis declined to comment.

“This is a part of the statement on McCarrick. Study it, and then I’ll speak,” the pope said, according to Crux, another Catholic outlet.

The reformist pontiff is divisive within the ranks of the Vatican, and Viganò’s letter provided dramatic evidence of how rivalries are being amplified as the church struggles to deal with abuse cases in Ireland, the United States, Australia and Chile.

Some of Francis’s critics, including Viganò, are calling for the pope to step down.

The Vatican had no comment.

The letter was the latest development stemming from a fresh wave of allegations related to clergy sex abuse and its coverup. Rumors that had swirled for decades about McCarrick exploded in June when Francis suspended the cardinal. Last month, McCarrick, facing credible allegations of abusing seminarians and minors, became the first U.S. cardinal in history to resign.

Viganò, 77, was the Holy See’s apostolic nuncio, or ambassador, in Washington from 2011 until 2016. He has been a lightning rod within the Vatican who lost a power struggle in Rome under Benedict, emerged as a Francis critic and reportedly ordered the halt of an investigation into alleged sexual relations between an archbishop in Minnesota and seminarians.

Jason Berry, who has written several investigative books about the Vatican, said he believes this is the first time a pope has been accused from within.

“From within the Vatican hierarchy, from within the Roman Curia, I don’t think anyone has ever publicly accused a pope of covering up for a sex abuser,” Berry said. “That’s why this is such a big deal.”

Viganò’s letter said that McCar­rick had been privately sanctioned under Benedict — though only after years of warnings about his alleged behavior toward seminarians and young priests — not toward minors. Viganò wrote that the measures, taken “in 2009 or 2010,” banned McCarrick from traveling, holding Mass or participating in public meetings.

Yet McCarrick appears to have done essentially the opposite. He regularly appeared as a speaker and celebrant at church functions and represented the church in prominent foreign diplomatic efforts in places such as China and Iran. A video from 2013 shows Benedict warmly greeting McCarrick in Rome, at the pope’s resignation (and the subsequent election of the new pope), where McCarrick gave round-the-clock television interviews and stayed at a seminary.

It wasn’t immediately clear why a pope taking the dramatic step of suspending a cardinal from ministry, as Viganò said, wouldn’t monitor McCarrick in any way.

However, when the archdiocese of New York last year began its investigation into an altar boy’s allegation against McCar­rick — the first accusation involving a youth — the Vatican ambassador Archbishop Christophe Pierre told McCarrick to be less public while the probe was underway, a person familiar with McCar­rick said Sunday. McCar­rick nonetheless still appeared in public as he wished, the person said, including attending an ordination ceremony in May in his cardinal’s garb.

Viganò’s letter says that in 2013, he met Francis and told the new pope face to face that there was “a dossier this thick” about McCarrick. He says he then told Francis about Benedict’s order that McCarrick remove himself from public life.

“He corrupted generations of seminarians and priests and Pope Benedict ordered him to withdraw to a life of prayer and penance,” Viganò says he told Francis. “The Pope did not make the slightest comment about those very grave words of mine and did not show any expression of surprise on his face, as if he had already known the matter for some time, and he immediately changed the subject.”

Barry Coburn, McCarrick’s lawyer, said in a statement: “These are serious allegations. Archbishop McCarrick, like any other person, has a right to due process. He looks forward to invoking that right at the appropriate time.”

He declined to elaborate further.

It was not possible to reach Benedict or his representatives. Francis has not commented previously about what he was told about McCarrick, and Vatican spokesman Greg Burke did not respond Sunday to requests seeking comment.

In the divided American Catholic Church, Francis’s comments and teachings about everything from immigration and global warming to the death penalty are frequently adopted or rebuffed along partisan lines.

The Viganò document uses American culture-war lingo, such as “right-wing” and “left-wing,” and concludes the letter by blaming “homosexual networks” for sexual abuse and corruption.

Conservative American Catholics who have suspected Francis of surreptitiously opening the door for liberalizing changes around sex and marriage have in recent years focused on the increased acceptance of LGBT people. Common targets for right-wing blogs such as LifeSite and Church Militant are bishops and cardinals they deem too moderate or liberal. Constantly on this list is D.C.’s Donald Wuerl, Chicago’s Blasé Cupich and Joseph Tobin of Newark. All are named by Viganò as being linked by “wickedness.”

In a statement provided by the Archdiocese of Chicago, Cupich corrected details laid out by Viganò about the sequencing of two events in Cupich’s career.

“As for the rest of the ‘testimony,’ a thorough vetting of the former nuncio’s many claims is required before any assessment of their credibility can be made,” Cupich wrote.

In the letter, Viganò described several figures who could corroborate parts of his account. Those people could not be reached Sunday.

Before moving to the District, Viganò spent time as a delegate within the Secretary of State’s office, working with the Vatican’s embassies around the world.

“I can imagine Viganò wanted to unburden his conscience,” said Marcello Pera, a retired professor who knows Viganò, co-authored a book with Benedict and has spoken critically about the direction of the church under Francis.

“The author is a reliable person who has suffered because of events,” Pera said. “His warnings were not listened to.”

Viganò was sent to Washington — reportedly as punishment — in 2011 and was there until May 2016. He arranged a controversial meeting between Francis and an American woman, Kim Davis, who had lost her job as a municipal clerk for refusing to issue marriage licenses to same-gender couples. Allies of Francis alleged that Viganò had set up the pope and that Francis didn’t intend to affirm Davis’s cause.

The letter also includes an allegation against Wuerl, D.C.’s current archbishop and McCarrick’s successor. He is a close ally of Francis and is already under scrutiny following a grand jury report in Pennsylvania about clerical child sex abuse and an alleged coverup. Wuerl for years led the diocese of Pittsburgh.

Viganò is vague in the allegation against Wuerl. The letter says “obviously” Wuerl knew about Benedict’s restrictions on McCar­rick because the then-ambassador, Pietro Sambi, was “responsible, loyal and direct” and must have told him. Viganò says he brought up the subject himself with Wuerl, and he writes that Wuerl “was fully aware of it.”

Wuerl’s spokesman, Ed McFadden, denied the report.

“In spite of what Archbishop Viganò’s memo indicates, Cardinal Wuerl did not receive any documentation or information during his time in Washington regarding any actions taken against” McCarrick, he said Sunday.

Winnie Obike, who is running as a Republican for a seat in Maryland’s House of Delegates and who has been circulating a petition demanding Wuerl’s resignation over the Pennsylvania report, said Sunday that she thought Viganò’s letter made Wuerl seem even more culpable, and Francis as well. “The moral authority of Pope Francis is shattered in my mind,” she said.

Pitrelli reported from Moena, Italy. Boorstein reported from Washington. Julie Zauzmer in Washington contributed to this report.