Bishop Michael Hoeppner of the Diocese of Crookston resigned Tuesday after a request to step down by Pope Francis and an investigation that showed he had covered up a sex abuse allegation against a priest.

Hoeppner is the first U.S. Catholic bishop to be disciplined under new Vatican protocols for reviewing and sanctioning bishops for sex abuse or coverups. The 2019 guidelines were put in place to enforce greater accountability of bishops when there are reports of abuse by clergy under their supervision.

Hoeppner, 71, was accused of pressuring a former deacon candidate to recant his statement that he was sexually abused as a teen by the Rev. Roger Grundhaus, a popular diocesan priest. Grundhaus has denied the abuse and Hoeppner has denied he tried to cover up the abuse claim.

The Vatican authorized an investigation into Hoeppner in 2019 for "acts or omissions intended to interfere with or avoid civil or canonical investigations of clerical sexual misconduct."

In a statement Tuesday to Catholics in the Crookston diocese, Hoeppner said: "I apologize to you, as I have apologized to our Holy Father, for my failures in governing as bishop. It has been a joy and a blessing for me to have served as your bishop for the past 13-plus years."

It was unclear what, if any, other sanctions were imposed on Hoeppner. The Rev. Richard Pates, bishop emeritus of the Des Moines Diocese, will assume the duties of bishop in Crookston until a new bishop is designated.

Hoeppner allegedly pressured deacon candidate Ron Vasek not to mention his allegation against Grundhaus, even coercing Vasek to sign a letter indicating the abuse did not happen.

Vasek said he was coerced to sign the letter in 2015, and later that year the diocese was court-ordered to reveal a list of priests facing allegations of sexual misconduct. Grundhaus' name did not appear on the list.

Hoeppner was among at least four U.S. Catholic bishops under investigation for child abuse or mishandling child abuse reports, said Anne Barrett Doyle, co-director of BishopAccountability, a Massachusetts-based online archive of global clergy abuse. He is the first to be asked to resign, she said.

Doyle, who has monitored bishops' role in abuse cases for more than a decade, said she still doesn't believe there's enough "accountability" in the Vatican process.

"Some might point to his firing as a sign of reform," Doyle said. "Seen differently, however, it shows that the church still isn't serious about punishing coverup. ... He remains not only a priest, but a bishop, with the prestige and financial benefits that status entails."

Twin Cities Archbishop Bernard Hebda supervised the initial Hoeppner investigations, which were forwarded to the Vatican. The final of three reports, containing 1,533 pages of documentation, was submitted earlier this year. Archdiocesan officials did not comment on Hoeppner's resignation.

The abuse victims' rights organization, the Survivors Network of Those Abused By Priests (SNAP), issued a statement Tuesday from executive director Zach Hiner.

"We are glad that one less diocese in the U.S. is led by a prelate who put their reputation over the protection of children," said Hiner. "We hope that the results of the investigation will still be released and that the Vatican will not use this resignation as an excuse to keep the facts from being made public."

Hoeppner grew up in Winona and was ordained a priest in Rome in 1975. He served in several parish and administrative positions in the Winona Diocese before he was named bishop of Crookston in 2007.

The Crookston Diocese, which stretches from Moorhead to Baudette, is home to about 35,000 Catholics.