This gun was seized Friday at Reagan National Airport after a man had it in his carry-on luggage. (COURTESY PHOTO)

A Fairfax man who authorities say mistakenly left a loaded 9mm semiautomatic pistol in his carry-on luggage was detained when he tried to pass through a security checkpoint at Reagan National Airport, officials said Tuesday.

An X-ray machine detected the weapon holstered inside a leather carrying case that also contained a second clip of ammunition when the man sent his carry-on luggage through a checkpoint machine Friday morning.

Elwood Kirkman, 59, was briefly detained by airport police and charged with a misdemeanor weapons offense under Virginia law. The gun was confiscated, but Kirkman was released and allowed to continue his trip to Dallas, the Transportation Security Administration said.

The announcement Tuesday morning was the agency’s first disclosure of the incident, which occurred five days earlier.

TSA spokeswoman Lisa Farbstein said the incident was not related to terrorism. “If there’s a nexus to terrorism, we’ll be sure to let everyone know,” she said. “Just a forgetful passenger. With that said, passengers who own guns need to know where the guns are at all times.”

This was the second time in two months that X-ray machines have discovered weapons at a Washington-area airport. In September, a Mount Airy woman bound for China was charged with a misdemeanor after the TSA said she attempted to carry two “artfully concealed” combat knives in her carry-on luggage through a checkpoint at Dulles International Airport.