By David Shepardson

WASHINGTON (Reuters) -A group representing major U.S. airlines and aviation unions on Monday wrote to U.S. Attorney General Merrick Garland asking the Justice Department to crack down on the growing number of disruptive and violent air passengers.

The Justice Department did not immediately comment on the letter, first reported by Reuters.

The letter from Airlines for America, which represents American Airlines, Delta Air Lines, United Airlines, Southwest Airlines and others, along with major unions said the “incidents pose a safety and security threat to our passengers and employees, and we respectfully request the (Justice Department) commit to the full and public prosecution of onboard acts of violence.”

The head of the Federal Aviation Administration (FAA), Steve Dickson, in January imposed a zero-tolerance order on passenger disturbances aboard airplanes after supporters of former U.S. President Donald Trump were disruptive on some flights around the time of a Jan. 6 U.S. Capitol attack.

Monday’s letter added that the airlines and unions hope the Justice Department “will commit to taking action, along with coordination with the FAA, to ensure that egregious onboard conduct is fully and criminally prosecuted, sending a strong public message of deterrence, safety and security.”

The letter to Garland said that since the FAA’s zero- tolerance policy was announced, the agency has received more than 3,039 reports of unruly behavior and has opened 465 investigations into assaults, threats of assault or interference with crew members.

More than 2,000 cases included passengers refusing to wear face masks as required on all airplanes.

The U.S. Transportation Security Administration (TSA) on April 30 extended a federal face mask mandate on airplanes and in airports through Sept. 13.

(Reporting by David Shepardson, Editing by Franklin Paul and Howard Goller)