WASHINGTON (AP) — U.S. officials say they are referring fewer unruly airline passengers to the FBI for possible prosecution than they did during the pandemic, although they say the number of incidents remains too high.

The Federal Aviation Administration said Wednesday that it referred 43 reports to the Federal Bureau of Investigation during the past year. That brings the total to more than 310 since late 2021.

It is not clear how many cases resulted in prosecution.

Airlines have reported more than 1,240 cases to the FAA this year. compared with nearly 6,000 in 2021. Relatively few of them are deemed serious enough to be passed along to the FBI for investigation and potential filing of criminal charges.

The FAA said the rate of passenger misbehavior has dropped by more than 80% since early 2021, when many confrontations with flight attendants and other passengers started with travelers who objected to wearing a face mask in the midst of a deadly global pandemic.

A federal judge struck down the mask rule in 2022, leaving airlines, airports and mass transit systems to make their own decisions about mask requirements. The Biden administration did not appeal the decision. Airlines and Republican politicians urged the administration to let the rule die.

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“There’s absolutely no excuse for unruly behavior,” FAA Administrator Mike Whitaker said Wednesday. “It threatens the safety of everyone on board, and we have zero tolerance for it.”

Referrals in the past year included passengers who tried to break into the cockpit, assaulted airline crew members or other passengers, or threatened others on the plane.

The FAA can propose civil penalties up to $37,000 but lacks authority to file criminal charges.

The agency announced a “zero-tolerance policy” in January 2021 under which it levied fines instead of issuing warning letters. Late that year, it struck a deal with the FBI to increase prosecutions.