Officers with the Transportation Security Administration stopped a traveler from Pennsylvania from allegedly bringing a loaded handgun onto his flight at Newark Liberty International Airport on Saturday.

TSA officials say an agent spotted the 9mm handgun at the security checkpoint’s X-ray machine. The gun was found inside a backpack.

The traveler was taken into custody. He also faces up to $15,000 in fines.

TSA officials say that agents have prevented more than 4,000 guns from getting through security nationwide this year.