Four soldiers were injured in an explosion near the US air base Kadena on the southern Japanese island of Okinawa while the military was defusing unexploded shells, Japanese media reported on Monday.
The detonation occurred in a building used to dispose of unexploded ordnance in the village of Yomitan. It is part of an ammunition depot adjacent to a US military base that is also used by the Japanese military.
The 15th Ground Self-Defence Brigade in Naha said the explosion occurred when unexploded shells were being collected and transported to a storage facility.
Okinawa is home to 70% of all US military facilities in Japan.
Last November, a US military base in the Hasakah province in north-eastern Syria was hit by a missile strike. Five missiles were fired at the base. Explosions were heard on the military facility’s grounds.