MINNEAPOLIS (AP) _ U.S. Bank Stadium officials have fired the firm that was providing the facility's security after an investigation showed it didn't comply with state regulations and licensing rules.

The investigation also found that Chicago-based Monterrey Security had unlicensed workers, employees that would normally be disqualified from working and billing irregularities. Reports say that two other firms, Whelan Security and G4S, are taking over stadium and event security.

Minnesota Sports Facilities Authority chairman Michael Vekich says the transition went smoothly.

Monterrey Security won the contract for building and event security before the stadium opened in 2015. Messages left with offices in Minneapolis and in Chicago weren't immediately returned to The Associated Press.

The Vikings say in a statement that they support the change. They host the Detroit Lions Sunday.