VATICAN CITY -- Pope Francis has authorized a "thorough study" of Vatican archives into how a prominent American cardinal advanced through church ranks despite allegations that he slept with seminarians and young priests, the Vatican said Saturday.

The Vatican said it was aware that such an investigation may produce evidence "that choices were taken that would not be consonant with a contemporary approach to such issues." But it said Francis would "follow the path of truth, wherever it may lead."

The statement did not address specific allegations that Francis himself knew of sexual misconduct allegations against now ex-Cardinal Theodore McCarrick in 2013 and rehabilitated him anyway from sanctions imposed by Pope Benedict XVI.

Francis has said he would not say a word about those allegations, lodged by a retired Vatican ambassador.

Depending on the scope of the investigation, Francis' actions may be found to have been inconsistent with what he now considers unacceptable behaviour.

"Both abuse and its coverup can no longer be tolerated and a different treatment for bishops who have committed or covered-up abuse in fact represents a form of clericalism that is no longer acceptable," the statement said.

The Vatican knew as early as 2000 that seminarians complained that McCarrick pressured them to sleep with him. The Rev. Boniface Ramsay, a professor at a New Jersey seminary, wrote a letter to the Vatican in November 2000 relaying the seminarians' concerns after McCarrick was named archbishop of Washington.

St. John Paul II still went ahead with the nomination and made McCarrick a cardinal the following year. McCarrick resigned as Washington archbishop in 2006 after he reached the retirement age of 75.

 Francis accepted McCarrick's resignation as a cardinal in July after a U.S. church investigation determined that an allegation that he groped a teenage altar boy in the 1970s was credible. Since then, another man has come forward saying McCarrick molested him when he was a young teen and other men have said they were harassed by McCarrick as adult seminarians and young priests.

The scandal has created a crisis in confidence in the U.S. hierarchy, since it was apparently an open secret that McCarrick, now 88, would invite seminarians to his New Jersey beach house, and into his bed.

Faced with a loss of credibility, U.S. bishops announced they wanted a full-scale Vatican investigation into how McCarrick was able to rise through the ranks, despite his misconduct.

The Vatican statement Saturday made clear an investigation would take place.