(NEXSTAR) – The Federal Aviation Administration said Thursday that it had referred 37 of the “most serious” cases of unruly airline passengers to the FBI for criminal case review.

The FBI will then determine whether any of the cases “merit potential prosecution” to its field offices for further investigation, according to the FAA.

“Let this serve both as a warning and a deterrent: If you disrupt a flight, you risk not just fines from the FAA but federal criminal prosecution as well,” said FAA Administrator Steve Dickson in a joint statement issued by the FAA and FBI on Thursday.

The 37 cases referred to the FBI this week were among 227 of the most egregious instances of unruly or disruptive behavior that had been reported to the FAA since enacting its “zero-tolerance” policy in January. The FAA has initiated civil enforcement action against all 227 individuals, levying fines of up to $37,000 per each violation.

In total, the number of cases reported to the FAA is much, much higher. Since the beginning of 2021, the FAA has received 5,033 cases of unruly behavior on flights, including 3,642 incidents described as “mask-related.”

The FAA could not provide specific details of the 37 “most serious” cases that have been referred to the FBI. A representative for the FAA could only say these passengers exhibited especially egregious behavior.

Along with Thursday’s announcement, the FAA released a new PSA which “highlights real consequences for disruptive behavior.”

The FAA has so far proposed collective fines of at least $1,100,000 since enacting its zero-tolerance policy in January. At the time, the FAA described a “disturbing increase” in disruptive behavior, specifically noting a “proliferation” of such conduct “following the January 6, 2021 violence at the U.S. Capitol,” according to an order signed by Dickson.

In addition to fines, passengers who violate FAA regulations or federal laws are also subject to possible federal criminal prosecution.

“This is a priority for both agencies,” said Dickson, referring to the 37 “egregious” cases brought before the FBI.