TSA acknowledged that “a passenger did in fact pass through a standard screening TSA checkpoint with a firearm at Hartsfield-Jackson Atlanta International Airport on January 2. TSA will hold those responsible appropriately accountable.”

The incident happened amid the partial federal shutdown that has left TSA officers working without pay since Dec. 22.

TSA said the checkpoint was fully staffed at the time, and said the rate of unscheduled absences that day, at 5 percent, was the same as a year ago.