At least four people have been injured following an explosion near a U.S. military air base in Japan. Local and defense ministry officials said that four Japan Ground Self-Defense Force (SFD) members suffered slight injuries following the incident at Kadena Air Base in Okinawa on Monday.

Japanese officials say an explosion at a storage site for unexploded ordnance at a U.S. military base on Japan’s southern island of Okinawa injured four Japanese soldiers.

An explosion rocked a Japanese military facility located within the US-run Kadena Air Base in Okinawa on June 9, according to the Japanese defense ministry. The blast occurred at a Japan Self-Defense Forces (SDF) site inside the base,