A leaked copy of a report found Wednesday contains Germany's Catholic Church admitting to at least 3,766 instances of child abuse between 1946 and 2014, according to Die Zeit and Spiegel Online.
The Vatican hasn't responded to Archbishop Carlo Maria Vigano's allegations against the pope and some two dozen other Vatican and US officials, but has promised "clarifications" that could come after Francis' meeting Thursday with the USA delegation.
The Feb. 21-24 meeting at the Vatican is believed to be the first of its kind, and signals a realization at the highest levels of the church that clergy sex abuse is a global problem and not restricted to the Anglo-Saxon world, as many church leaders have long tried to insist.
During the sex abuse scandal in Chile earlier this year, Pope Francis was forced to apologize for "errors in judgment" after calling accusations of cover-up against Bishop Juan Barros a "calumny" for years.
Last month, a Pennsylvania grand jury report detailed more than 1,000 children were sexually abused by more than 300 clergy members.
DiNardo requested a full-fledged Vatican investigation into the McCarrick affair, and said he also wanted answers to allegations that a string of Vatican officials knew of McCarrick's misdeeds since 2000, but turned a blind eye.
The McCarrick scandal took on crisis proportions two weeks ago after the Vatican's former U.S. ambassador, Archbishop Carlo Maria Vigano, accused two dozen Vatican and USA cardinals and bishops by name of covering up for McCarrick.
Francis' key cardinal advisers announced the decision Wednesday, a day before Francis meets with U.S. church leaders, who are facing fresh accusations following the bombshell grand jury report.
The pope met Cardinal Daniel DiNardo of Galveston-Houston, who leads the US Conference of Bishops, and Cardinal Sean O'Malley of Boston, who advises the pope on sex abuse issues. The U.S. bishops who will meet with Francis on Thursday are expected to press the pope on how that trial would proceed. Two dioceses also had announced allegations of inappropriate contact between Archbishop McCarrick and seminarians, resulting in settlements totaling more than $100,000. "He tries to uncover the sins, so they are visible in order to scandalize the people".
In other eyebrow-raising comments on Tuesday, a top aide to both Francis and Benedict said the sex abuse scandal was such a game-changing catastrophe for the church that it amounted to its "own 9/11".
This comes as an archbishop accuses the Pope of covering up sexual abuse allegations against an American cardinal.