Pope Francis has refused to say whether he knew about child sexual abuse claims against the former archbishop of Washington, five years before his resignation last month.

Theodore McCarrick was forced to quit after a US church investigation determined that an accusation he had sexually abused a minor was credible. He was one of the highest-ranking church officials accused in a scandal that has rocked the faith’s 1.2 billion adherents since reports of systemic abuse were first published by the Boston Globe in 2002.

Since his resignation, another man has come forward to say McCarrick molested him starting when he was 11, and several former seminarians have said he abused and harassed them when they were in seminary.

An 11-page text subsequently penned by Archbishop Carlo Maria Vigano, the Vatican’s retired ambassador to the US, has subsequently claimed that Pope Francis has known about the allegations since 2013.

He claimed that that the pair had discussed the allegations against McCarrick at the time. McCarrick was already under sanction at the time, but Francis rehabilitated him, he said.

Asked about the document, the pontiff declined to confirm or deny the claims it made.

It “speaks for itself”, he said, adding that he would not comment on it.

He said he had read Archbishop Vigano’s document and trusted journalists to judge for themselves. “It’s an act of trust,” he said. “I won’t say a word about it.”

The National Catholic Register and another conservative site, LifeSiteNews, published Archbishop Vigano’s text over the weekend, as the Pope ended a two-day visit to Ireland dominated by the clerical sex abuse scandal.

There, Francis begged forgiveness for the “open wound” of church abuse in the country during an address to pilgrims at a shrine in Knock, Co Mayo. Later, in Dublin, he admitted the Catholic Church hierarchy had been guilty of cover-ups and failing to show compassion.

In his letter Archbishop Vigano, a conservative with well-known, hardline anti-gay views, urged the reformist Pope to resign over what he called Francis’s own culpability in covering up Mr McCarrick’s alleged crimes.

“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,” the 77-year-old wrote.

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.

Archbishop Vigano apparently sought to answer some of those questions.

His letter identified by name the Vatican cardinals and US archbishops who were informed about the McCarrick affair. He said documents backing up his version of events are in Vatican archives.

Pope Francis visits Ireland – in pictures Show all 55 1 /55 Pope Francis visits Ireland – in pictures Pope Francis visits Ireland – in pictures Pope Francis celebrates the Holy Mass at the Phoenix Park, in Dublin AP Pope Francis visits Ireland – in pictures Pope Francis arrives at Phoenix Park for a Papal Mass of the World Meeting of Families in Dublin EPA Pope Francis visits Ireland – in pictures A vigil takes place at the site of the mass grave which contained the remains of 796 named babies from the Bon Secours Mother and Baby home in Tuam. The vigil coincides with the Phoenix park mass which is taking place in Dublin held by Pope Francis. Excavations at the site in 2017 revealed underground structures which held babies bodies with ages ranging from 35 weeks to three years old with most of the dead buried in the 1950s when the facility was run by the Bon Secours Sisters, a Catholic religious order of nuns who received unmarried pregnant women to give birth Getty Pope Francis visits Ireland – in pictures An aerial view of the crowd at Phoenix Park Getty Images Pope Francis visits Ireland – in pictures Children queue for communion during Pope Francis' closing Mass PA Pope Francis visits Ireland – in pictures The Stand4Truth rally gathers outside a former Magdalene laundry in Dublin as part of the demonstrations against clerical sex abuse PA Pope Francis visits Ireland – in pictures Pope Francis leads the Holy Mass at Phoenix Park AFP/Getty Pope Francis visits Ireland – in pictures Pope Francis arrives to celebrate the Holy Mass at the Phoenix Park AP Pope Francis visits Ireland – in pictures The names of the victims are read out as a vigil takes place at the site of the mass grave which contained the remains of 796 named babies from the Bon Secours Mother and Baby home Getty Images Pope Francis visits Ireland – in pictures Pope Francis leads the Holy Mass at Phoenix Park AFP/Getty Pope Francis visits Ireland – in pictures A member of the clergy carries a bowl of incense PA Pope Francis visits Ireland – in pictures Pope Francis celebrates the Holy Mass at the Phoenix Park, in Dublin, Ireland, Sunday, Aug. 26, 2018. Pope Francis is on the second of his two-day visit to Ireland. (AP Photo/Matt Dunham) Matt Dunham AP Pope Francis visits Ireland – in pictures A vigil takes place at the site of the mass grave which contained the remains of 796 named babies Getty Images Pope Francis visits Ireland – in pictures Members of the public pray as they watch Pope Francis deliver a Papal Mass of the World Meeting of Families at Phoenix Park EPA Pope Francis visits Ireland – in pictures Pope Francis attends the closing Mass at the World Meeting of Families at Phoenix Park in Dublin PA Pope Francis visits Ireland – in pictures Pope Francis passes by a banner of a protester as he leaves St Mary's Pro-Cathedral AP Pope Francis visits Ireland – in pictures Pope Francis speaks during his visit to the Capuchin Day Centre for Homeless in Dublin AP Pope Francis visits Ireland – in pictures Pope Francis waves to the waiting crowds on Christchurch PA Pope Francis visits Ireland – in pictures Pope Francis waves to the waiting crowds on College Green PA Pope Francis visits Ireland – in pictures Members of the public wave at Pope Francis as he travels through the city Getty Images Pope Francis visits Ireland – in pictures Pope Francis laughs as he leaves St Mary's Pro Cathedral during his visit to Dublin Reuters Pope Francis visits Ireland – in pictures Two boys wave flags after climbing a post as they wait for Pope Francis Getty Pope Francis visits Ireland – in pictures Pairs of baby shoes are hung from black ribbons on Gardiner Street in Dublin in memory of the children who died at the Bon Secours Mother and Baby Home in Tuam, Co Galway PA Pope Francis visits Ireland – in pictures Crowds on O'Connell Street PA Pope Francis visits Ireland – in pictures DUBLIN, IRELAND - AUGUST 25: (NO SALES) In this handout image provided by Maxwell Photography for 2018 WMOF2018, Pope Francis and Taoiseach Leo Varadkar greet a child at Dublin Castle on August 25, 2018 in Dublin, Ireland. Pope Francis is the 266th Catholic Pope and current sovereign of the Vatican. His visit, the first by a Pope since John Paul II's in 1979, is expected to attract hundreds of thousands of Catholics to a series of events in Dublin and Knock. During his visit he will have private meetings with victims of sexual abuse by Catholic clergy. 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The Vatican’s ambassador to the US from 2011 to 2016, Mr Vigano said his two immediate predecessors “did not fail” to inform the Holy See about accusations against Mr McCarrick, starting in 2000.

Archbishop Vigano said he himself sent at least two memos about him.

He said Pope Benedict XVI eventually sanctioned McCarrick in 2009 or 2010 to a lifetime of penance and prayer, and to no longer celebrate mass in public or travel.

He said Francis asked him about McCarrick when they met on 23 June 2013, three months after he was elected to the papacy

The meeting took place at the Vatican’s Santa Marta hotel where the Pope lives, he added.

There, Archbishop Vigano claimed that he told the new pontiff: “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.”

Shortly afterwards Archbishop Vigano wrote that he was surprised to find that McCarrick had started travelling on missions on behalf of the church, including to China. He was also one of the Vatican’s intermediaries in the US-Cuba talks in 2014.

Archbishop Vigano’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 he enjoyed a fairly public retirement.

But Archbishop Vigano insisted the sanctions had been imposed, and said a former counsellor in the embassy at the time was “prepared to testify” about the “stormy” meeting when Mr McCarrick was informed of them.

Barry Coburn, McCarrick’s civil attorney, said the allegations in the letter were “serious”.

“Archbishop McCarrick, like any other person, has a right to due process. He looks forward to invoking that right at the appropriate time,” he said in a statement.