The Vatican has authorized an investigation into a U.S. bishop accused of sexual harassment of adults Thursday, as a U.S. delegation met with the pope over the latest chapter in the Catholic Church's long-running sex abuse and cover-up scandal that have also implicated Francis himself.

The Vatican announced that Pope Francis had accepted the resignation of West Virginia Bishop Michael Bransfield, and had named a temporary administrator for his Wheeling-Charleston diocese.

The administrator, Baltimore Bishop William Lori, said in a statement that Francis had instructed him to "conduct an investigation into allegations of sexual harassment of adults against Bishop Bransfield."

The Rev. Michael J. Bransfield expresses his thanks in his closing remarks during his ordination and installation, becoming the eighth Roman Catholic bishop of West Virginia, during services at St. Joseph Cathedral in Wheeling, W.Va., on Feb. 22, 2005. Scott McCloskey / AP file

Lori vowed to conduct "a thorough investigation in search of the truth into the troubling allegations against Bishop Bransfield."

Cardinal Daniel DiNardo, head of the U.S. Conference of Catholic Bishops, is heading the U.S. delegation and is accompanied by Boston Cardinal Sean O'Malley, Francis' top sex abuse adviser, and other officials from the U.S. conference. He requested the audience last month following revelations that a now-disgraced ex-cardinal, Theodore McCarrick, had risen through church ranks despite allegations of sexual misconduct that were known in U.S. and Vatican circles.

As well as requesting a full-fledged Vatican investigation into the McCarrick affair, DiNardo wants answers to allegations that a string of Vatican officials — including Francis — have known of McCarrick's misdeeds since 2000, but turned a blind eye.

U.S. cardinal Daniel DiNardo attends a mass at the St Peter's basilica before the conclave at the Vatican in 2013. Gabriel Bouys / AFP - Getty Images file

The Vatican hasn't responded to allegations by its former ambassador to the U.S., Archbishop Carlo Maria Vigano, that Francis rehabilitated McCarrick from sanctions imposed by Pope Benedict XVI over allegations McCarrick would routinely invite seminarians to his beach house and into his bed.

Francis removed McCarrick as a cardinal in July after a U.S. church investigation said an allegation that he groped a teenage altar boy in the 1970s was credible. After news broke of the sanction, several former seminarians and priests came forward to report that they too had been abused or harassed by McCarrick as adults.

The McCarrick affair — coupled with revelations in the Pennsylvania grand jury report detailing decades of abuse and cover-up in six dioceses — has fueled outrage among the rank-and-file faithful who had trusted church leaders to reform themselves after the abuse scandal first erupted in Boston in 2002.

The outrage has also been directed at Francis and the Vatican and has fueled conservative criticism of Francis' mercy-over-morals priorities.

Francis has responded with a series of initiatives aimed at trying to convince the faithful that he "gets it" and is prepared to take measures to put an end to what he has called the "culture of cover-up" in the church.

On the eve of the U.S. audience, Francis announced he was summoning the presidents of bishops conferences around the world to a February summit to discuss prevention measures and protection of minors and vulnerable adults.

In his capacity as president of the U.S. conference, DiNardo has been outspoken in calling for greater protections for children and accountability. He announced in August that he wanted a Vatican investigation — known as an apostolic visitation — into the McCarrick affair, working in concert with a group of predominantly lay experts.

But even DiNardo's own record on protecting children has now come into question. On the eve of his audience with Francis, The Associated Press reported that two victims in Houston had accused him of not doing enough to stop a priest who was arrested this week on sexual abuse charges.

"We are faced with a spiritual crisis that requires not only spiritual conversion, but practical changes to avoid repeating the sins and failures of the past," DiNardo said in an Aug. 16 statement. "I have no illusions about the degree to which trust in the bishops has been damaged by these past sins and failures."