In a 2015 file photo, an airplane flies between the air traffic control tower and the Washington Monument at Washington’s Ronald Reagan National Airport. (Jacquelyn Martin/AP)

Three loaded guns were discovered at airport checkpoints at Reagan National Airport in August, officials said, bringing the total number of weapons found this year to nine.

On Wednesday, a 20-year-old Oklahoma man was caught at an airport checkpoint carrying a .40-caliber handgun loaded with 12 bullets.

Airport police identified him as Richard Keith Jackson of Holdenville, Okla. He was arrested and cited for carrying a weapon in an airport terminal. Officials with the Transportation Security Administration said that Jackson told them he had meant to leave the gun in his car but forgot.

Jackson’s arrest comes just five days after Cabal Rafael Gonzalez, 28, of Fairfax, was caught with a 9mm handgun loaded with six bullets. And on Aug. 6, TSA officers caught Michael Sellers, 40, of  Springfield, at a checkpoint with a .45-caliber handgun loaded with four bullets.

TSA officers discovered an Oklahoma man carrying this .40-caliber handgun loaded with 12 bullets in his carry-on bag at a security checkpoint at Reagan National Airport on Wednesday. (TSA)

For those keeping track, that makes three guns over a nine-day span.

Wednesday’s incident was the ninth time TSA officers have caught individuals traveling with guns, which are not allowed in carry-on bags. All firearms were confiscated, and the three men were cited on state weapons charges. TSA officials said the incidents were not related. Last year, TSA officers caught 13 guns at checkpoints at National Airport.

Meanwhile, on Monday, TSA officials caught an Alexandria man with a loaded gun at a security checkpoint at Baltimore-Washington International Marshall Airport. It was the 18th gun found at a BWI checkpoint this year. Last year, TSA officials caught 26 firearms at BWI checkpoints.

Alex Natal, 65, was carrying a 9mm handgun loaded with 13 bullets, including one in the chamber. Natal also had two magazines with another 12 bullets in his luggage. He told TSA officials that he forgot he had packed his loaded gun into his bag. Natal was cited by Maryland Transportation Authority Police on state weapons charges. Authorities also confiscated his gun and ammunition.

TSA officials remind travelers they can bring firearms with them when they travel, but they must be properly packed in checked baggage and declared. Ammunition must be packed separately from firearms.

TSA can assess penalties of up to $13,000 for travelers who bring weapons to airports. A typical first offense for carrying a handgun into a checkpoint is $3,900.