An explosion occurred at a U.S. Army base in Japan just after midnight local time, according to ABC News.

The Sagami Depot in Sagamihara, where the first blast took place, is about 25 miles southwest of Tokyo, Fox News reported.

Multiple explosions were reported at the scene, according to the International Business Times. Ten fire trucks and one helicopter were sent to fight the blaze.

The building where the explosion took place, the Sagami depot, houses the 35th Combat Sustainment Support Battalion, The Guardian reported.  The facility is concerned with army supplies and logistics.

Firefighters responded to the scene quickly, keeping it from spreading to nearby buildings. There are no reported injuries at this time as a result of the fire.

The building was not a hazardous waste facility, nor did it store ammunition or radiological materials, according to Fox News. The cause of the explosion remains unknown at this time.

No troops were stationed at the depot, though it is a workplace for about 200 personnel.

Three explosions were reported on the same base in April. Police later said that they believed the attack was carried out by a left-wing Japanese extremist group, according to the International Business Times.