A Morgantown, West Virginia, man pleaded guilty Wednesday to possessing an unregistered firearm after attempting to bring a flash-bang grenade through airport security in Pittsburgh.

Zachary Velling, 27, entered the plea before U.S. District Judge Mark R. Hornak in the Western District of Pennsylvania. The charge stems from an incident on November 12, 2024, when Velling placed his carry-on luggage through an X-ray machine at the main security checkpoint of Pittsburgh International Airport.

Transportation Security Administration officers spotted a suspicious object in the bag around 9:35 a.m. and alerted Allegheny County Police. Officers determined the item was an MK24 MOD 0,6 Bang/Flash diversionary hand grenade, which a bomb squad technician confirmed was live before it was removed from the area.

Federal law classifies the grenade as a firearm and destructive device. Prosecutors said it was not registered to Velling in the National Firearms Registration and Transfer Record. The FBI, Bureau of Alcohol, Tobacco, Firearms and Explosives, Allegheny County Police Department, and TSA investigated the case.

Velling faces a maximum sentence of up to 10 years in prison and a fine of up to $250,000. His sentencing is scheduled for January 7, 2027.

"Attempting to pass through airport security with any firearm or destructive device poses an unacceptable risk of harm to the innocent traveling public," Acting U.S. Attorney Troy Rivetti said in a statement. "This danger is heightened when, as in this case, the destructive device is possessed illegally."

Velling was previously charged in Allegheny County court with related state offenses that were later dismissed following the federal indictment.