Naha Airport on Okinawa is pictured in 2014. (Wikimedia Commons)

Japanese police say they arrested a U.S. airman Friday who had two live bullets in his carry-on luggage at an Okinawa airport.

MC Trang, 26, was taken into custody that afternoon after baggage inspectors found the bullets in Naha Airport’s domestic flight terminal, an Okinawa Prefectural Police spokesman said by phone Monday. The airman’s rank was also not available.

Police would not specify the caliber of the bullets, saying they were being analyzed.

Trang was held on suspicion of violating Japanese law on possession of firearms, swords and other weapons, the spokesman said. Some government spokespeople in Japan are required to speak to the media only on condition of anonymity.

Gun and ammunition ownership is tightly controlled in Japan, though it’s possible for hunters and target shooters with the U.S. military to own a firearm after a lengthy, expensive process.

The airman admitted the bullets were his but said he forgot they were in his bag, a spokesman for Tomishiro police said by phone Monday.

Trang is assigned to a base outside of Japan, the spokesman said. He was still in Japanese custody Monday.

“The 18th Wing is cooperating with local authorities on their investigation and providing SOFA-prescribed support” to Trang, Staff Sgt. Gary Hilton, a wing spokesman, said by email Monday.

SOFA is the status of forces agreement that outlines the rights and responsibilities of those in Japan as part of the U.S. military.

“The U.S. Air Force will hold anyone accountable who commits criminal acts under the applicable laws,” Hilton said.