MINNEAPOLIS (AP) — The Archdiocese of St. Paul and Minneapolis made serious mistakes in the way it handled allegations of clergy sexual misconduct in the last decade, Archbishop John Nienstedt acknowledged Thursday as he announced he has ordered an external review of all priest files.

Nienstedt apologized to victims in a column posted on the website of The Catholic Spirit, the archdiocese’s official newspaper, and said he knows the ultimate responsibility is his as head of the local church.

“My heart is heavy with the agony that these errors have caused,” he wrote.

The archdiocese has come under fire since a former employee claimed church leaders mishandled abuse allegations. Nienstedt’s top deputy has stepped down, police are investigating, and there have been public calls for Nienstedt to resign.

Nienstedt said sexual abuse of a minor or vulnerable adult is “reprehensible, morally repugnant and goes against Christ’s teachings to promote goodness, life and light. This is not who we are as the Catholic Church.”

And when perpetrated by a clergy member, “it is an egregious betrayal of a sacred trust,” he said.

Nienstedt has refused repeated interview requests from The Associated Press. But in an email to Minnesota Public Radio News on Wednesday, he denied any cover-up of abuse and said he has not offered to resign.

He wrote Thursday that policies governing misconduct allegations may not have been uniformly followed, and that he’s questioning the “prudence of the judgments that have been made.” He had previously set up a task force to review church policies, and said he is committed to implementing their recommendations.

Furthermore, he said he has ordered a review of “all clergy files by an outside firm,” but he didn’t specify who would be conducting that analysis.

“We must also be committed to honesty and transparency,” he wrote.

David Clohessy, national director of the Survivors Network of those Abused by Priests, said Nienstedt’s words are just more of the same and any external review would not be independent if ordered by the archbishop.

“Nothing he can say will matter. Only what he does matters,” Clohessy said. “And today he exposes no predators, disciplines no enablers, reveals no secrets, and deters no cover ups. It’s just more promises from a bishop who has repeatedly broken promises.”

Clohessy said secrecy is a key part of the problem. His group has called for the archdiocese to make public a list of 33 priests it has identified as having credible allegations of abuse lodged against them.

Nienstedt insists no offending priests are in active ministry. He said he would recommit himself to never knowingly assign a clergy member to a parish or school if he has concerns, and promised a rigorous analysis of priests before assignments are made.

Nienstedt also said the church must cooperate with authorities, and that media reports and letters from Catholics and the general public have made him “aware that there is real fear that some priests in ministry today constitute a danger to children.

“I could never knowingly allow such a situation,” he said.

The Star Tribune reported Thursday that the archdiocese spent nearly $11 million from 2003 through 2012 to cover costs associated with cases of sexual misconduct by priests. The figure includes payments to victims, as well as costs of supporting priests who have been removed from active ministry due to misconduct.