MINNEAPOLIS >> The two top leaders of the authority overseeing the Minnesota Vikings’ stadium resigned abruptly Thursday after weeks of criticism over the questionable use of luxury suites by officials’ family and friends, a practice that auditors labeled an ethical violation.

Authority Chairwoman Michele Kelm-Helgen announced her resignation first in a Thursday morning letter, saying it was in the public interest for her to step down from the Minnesota Sports Facilities Authority. Hours later, executive director Ted Mondale announced his own exit as top Republicans charting massive changes to stadium governance ramped up calls for him to also step aside.

The pair, and the authority as a whole, had been taking heat for months since their use of two luxury suites was first reported by the Star Tribune. A recent report from the Office of the Legislative Auditor last week found that nearly half of the tickets for those two suites were issued to friends and family members of top oversight officials, including Kelm-Helgen and Mondale.

“If I could go back and start over again, MSFA would have had a public discussion on the use of these suites and forbid the use of them by family and friends from the start,” Kelm-Helgen wrote.

Their departure leaves a leadership vacuum at the oversight board as Minnesota gears up to host the 2018 Super Bowl.

Democratic Gov. Mark Dayton appointed them both. And while he said he didn’t ask for either resignation, he credited them for recognizing their continued roles on the authority would “be a detriment.”

Kelm-Helgen repeatedly apologized to legislators during a hearing on the audit last week, but she and Mondale also defended the practice as commonplace among stadiums around the country.

No state laws were broken, but the auditor’s report said the practice violated a “core ethical principle” and that the marketing purpose of inviting friends, family and certain government employees to games and special events wasn’t clear. Several Democratic officials paid $200 or more back to the authority for games they attended after the Star Tribune first wrote about the scandal.

The authority has since changed its rules to bar the practice.

Republican legislators have been pursuing major changes to the authority’s structure. A bill that would drastically reshape the authority by giving the Legislature the power to appoint most of its members and eliminating Kelm-Helgen’s salary was due for another hearing Thursday afternoon.

Rep. Sarah Anderson, a Plymouth Republican behind that bill, said both officials’ resignations were the right move. But she called it “the tip of the iceberg when it comes to addressing the problems” at the oversight board, and said the four remaining authority commissioners should consider following suit. .

“Given the actions of Ms. Kelm-Helgen and Mr. Mondale, hopefully they take that as motivation,” Anderson said.

Dayton said he hasn’t decided whether he’ll appoint an interim chair once Kelm-Helgen formally departs in early March. But he bristled at the suggestion that the remaining authority members should also be removed, calling it an unfounded step for the new, $1.1 billion stadium, which just hosted its first NFL season.

“We need the stability of the existing members of the board to carry this thing forward,” the Democratic governor said.

The legislative auditor noted that lawmakers may have let their oversight of the authority slip. A panel charged with overseeing construction and operation of the stadium met just once in 2016, and Republicans have not yet appointed any members for 2017.

Anderson said they may have “took things for granted” that the stadium was being run properly.