The United States has confirmed reports of a thunderous explosion at one of its military bases in Japan.
The Pentagon said the explosion took place at a building early on Monday at the US Army Sagami General Depot in Sagamihara, a city located about 25 miles (40 kilometers) southwest of Tokyo, AFP reported.
"There are no reports of injury, and base firefighters and first responders are currently fighting the resulting fire to prevent its spread to nearby buildings," said US Navy Commander Bill Urban, a spokesman.
Japanese firefighters said on Monday that they were waiting the US military to provide information that exactly what was stored in the depot before dealing with the fire.
"We are coordinating with US fire units and we are waiting for people who know exactly what is inside to tell us what's inside," a Japanese duty officer at the Sagahimara fire bureau said.
"We have not poured water (on the warehouse) because it could make the situation worse, depending on what is inside," he said.
The Pentagon spokesman claimed that ammunition or radiological material was not stored at the warehouse.
"The storage building is not designated as a hazardous material storage facility as some initial reports indicated. We are in the process of determining the exact contents of the building," he said.
However, a video captured by a Japaense woman showed large orange sparks coming out from the massive structural blaze lighting up the night sky.
The woman stated that she repeatedly heard loud explosions for 10 to 15 minutes.
"Orange sparks were rising quite high. I couldn't see smoke but smelled something like gunpowder," she told the Japanese Broadcasting Corporation (NHK).