A loaded handgun was found at Pittsburgh International Airport on Tuesday.

A Butler County man found with a loaded handgun at Pittsburgh International Airport told security officers that he forgot he had it with him, authorities said.

The man, who is from Mars, was stopped Tuesday with a .380-caliber pistol loaded with five bullets, including one in the chamber, in his jacket pocket, according to the Transportation Security Administration.

The gun was detected in the jacket — which the man had placed in a checkpoint bin — by the X-ray monitor.

The incident marked the fifth gun found at the Pittsburgh airport security checkpoint this year. In 2019, TSA officers found 35 firearms at the checkpoint. In 2018, officers seized 34 guns.

TSA contacted Allegheny County Police, which responded, confiscated the gun and detained the man for questioning. He was later released. Police did not immediately return a telephone call.

Authorities did not release the man's name because the incident remains under investigation, and no charges have been filed.

He told officials that he forget he had the loaded gun with him, “even though it was just inches from his hand” in his pocket, according to a TSA news release.

“I forgot” is the most common excuse that TSA screeners hear when someone is caught with a gun at the airport checkpoint, authorities said.

TSA officials note that people who bring firearms to the checkpoint are subject to possible criminal charges from law enforcement.

In addition, TSA can assess civil penalties, including fines as high as $13,000 for gun violations. A typical first offense for carrying a handgun into a checkpoint is $4,100, according to the TSA website.

To travel with a gun, it must be unloaded in a locked hard-side case in checked baggage only.

Nationwide last year, authorities said, 4,432 firearms were discovered in carry-on bags at checkpoints across the country, averaging about 11.6 firearms per day — around a 7 percent increase from 2017.

In October, another man from Mars was stopped with a loaded 9 mm pistol at Pittsburgh International Airport.