LOS ANGELES — A total of 145 firearms were confiscated by security checkpoint personnel at five Los Angeles-area airports last year, and Thursday law enforcement officials are warning gun owners to familiarize themselves with the rules governing travel with weapons.

"Travelers should know that TSA can levy a civil penalty for bringing a firearm to a security checkpoint," Transportation Security Administration Federal Security Director Jason Pantages told reporters during a news conference Wednesday at Los Angeles International Airport. "The amount of the penalty, which can be as high as $15,000, depends on whether the firearm was loaded. And 87% of the firearms discovered here at LAX are loaded."

Authorities said 145 firearms were brought to TSA checkpoints last year at LAX, Long Beach Airport, Hollywood Burbank Airport, John Wayne Airport in Orange County and Ontario International Airport. LAX led the way, with 81 firearms discovered, up five from the previous year.

Nationwide, more than 6,700 firearms — 93% of them loaded — were brought by passengers to security checkpoints at 265 U.S. airports in 2023, up from 6,542 the previous year. Hartsfield-Jackson Atlanta International Airport, one of the nation's busiest airfields, saw the most, with 451.

Authorities said the increase in weapon discoveries is due in part to the steady rise in air travel following the pandemic.

TSA and local officials stressed that firearms cannot be taken on airplanes in carry-on luggage, even if the passenger has a concealed-weapon permit. Weapons must be packed in checked luggage, locked in a secure case.

Authorities said the penalties for trying to take a gun on an airplane can vary.

Los Angeles Airport Police Chief Cecil Rhambo said when a gun is found at a checkpoint, officers will respond and take possession of the weapon and check to determine if it is tied to any crimes or warrants. Officers will also check to see if there are "obliterated serial numbers" on the weapon. The passenger found with the weapon is also checked for warrants.

In addition to the possible TSA civil citation, people could be convicted of a misdemeanor for bringing a weapon to an airport security checkpoint. Rhambo said people who are convicted in such cases could be sent to a one-year diversionary program.

"After a year, the owner of the firearm is eligible to retrieve the weapon as long as they remain clear from any disqualifying issues such as a restraining order, some mental health issues or domestic violence incidents," he said.