For the second time this week, TSA agents at Portland International Jetport have found a loaded gun in a passengers' carry-on bag.

The first incident happened on Wednesday, when TSA agents found a loaded 9mm handgun in a woman's purse. The gun was located in a zippered outer pocket, and the woman told authorities she forgot it was in there.

On Thursday, agents spotted a gun in a man's backpack, as it passed through the checkpoint x-ray machine. The handgun was in a zippered carrying case, inside the bag. The Sun Journal reports TSA officials notified police, who confiscated the firearm and detained the man for questioning.

Passengers are allowed to travel with firearms, but TSA regulations state they must be unloaded and locked, and secured in luggage that's checked into the baggage compartment. Bringing a firearm to a TSA checkpoint could net a fine as high as $13,333, although most first-time offenders only pay about $4,100.