The explosion occurred at US military base in Okinawa, Japan, NHK reported.
According to the source, no one has been injured as a result of the explosion.
Police suspect that someone may have broken into the scene through the fence.
The suspects reportedly blew up a gas cylinder that was used at the base by the Japanese Defense Ministry's representatives.
About 70% of all US military bases in Japan are concentrated in Okinawa. Local authorities and public’s members have consistently advocated reducing the US military presence there.