An explosion at a U.S. military base near Tokyo set a warehouse on fire early Monday.
The army says there are no injuries, but that U.S. firefighters immediately rushed to the scene to stop the flames from spreading to other buildings.
Japanese firefighters say they will not try to out the blaze or make any efforts to fight it until they find out what is in the warehouse to avoid possibly making a dangerous situation worse.
Residents near the base in Sagamihara, south of Tokyo, reported hearing about 10 minutes of continuous explosions and smelling gunpowder in the air.
