Pope Francis has met the president of the US bishops' conference as his supporters closed ranks over the pontiff's handling of allegations of sexual misconduct by a US cardinal.

The Pope held talks with Cardinal Daniel Di Nardo and other senior members of the bishops' conference just 48 hours after ordering an investigation into Vatican archives concerning former archbishop of Washington Theodore McCarrick, who resigned in July.

Cardinal DiNardo yesterday "welcomed" the "additional steps Pope Francis is taking to ensure the faithful are protected from the evil of sexual assault".

The case of McCarrick triggered a storm in August after Archbishop Carlo Maria Vigano, a former Vatican envoy to Washington, accused the pope of ignoring allegations the prominent Catholic leader had abused a teenager decades ago.

Pope Francis was accused of lifting sanctions against McCarrick that his predecessor Benedict XVI had imposed - charges refuted yesterday by the Vatican's prefect for the Congregation for Bishops.

Canadian cardinal Marc Ouellett said Archbishop Vigano's "unjustified attack" was a "political manoeuver without any real foundation" that aimed "to incriminate the pope".

Cardinal Ouellett said he had told Archbishop Vigano in person that McCarrick "was supposed to obey certain conditions and restrictions due to the rumours surrounding his past behaviour".

After stepping down as archbishop of Washington in 2006, McCarrick "had been strongly advised not to travel and not to appear in public, so as not to provoke additional rumours in his regard.

"It is false to present the measures taken in his regard as 'sanctions' decreed by Pope Benedict XVI and revoked by Pope Francis," Cardinal Ouellett said in an open letter to Archbishop Vigano.

McCarrick escaped being sanctioned because "at that time, unlike today, there was not sufficient proof of his alleged guilt".

Cardinal Ouellett admitted that in his opinion "some suspicions provided by witnesses should have been further examined", but added that "the prelate in question knew how to defend himself very skillfully regarding the doubts that were raised about him".

His stinging letter, unusually blunt between churchmen, was a point-by-point rebuttal of Archbishop Vigano's statements.
He said the archbishop, who is in hiding and has issued his accusations exclusively through conservative Catholic media which are traditionally antagonistic towards the pope, had let himself "be convinced of this monstrous accusation".
Cardinal Ouellet said: "I conclude, therefore that your accusations are a political frame job devoid of any real foundation."
He urged Archbishop Vigano to "Come out of hiding, repent for your revolt and return to better feelings towards the Holy Father instead of worsening hostility against him".
He added: "Should not ministers of the truth above all stay away from calumny and defamation?"

Pope Francis has refused to comment on the Vigano accusation.

The Vatican has said further study of the entire documentation present in its archives may reveal the church's leadership took choices that would not live up to its contemporary guidelines on tackling cover-ups.

"We will follow the path of truth wherever it may lead," it said.