"It is impossible to determine the number of casualties right now, but several dozen have been killed and there are hundreds or even thousands injured," said a senior army commander.
The explosions are reported to have started at the defense ammunition depot in Musaga, south of Bujumbura.
Several areas in the densely populated city were affected, mainly by shrapnel damage.
Police confirm that dozens have been killed. A police source says the fire started in the warehouse where heavy weapons and ammunition were stored and then spread to other warehouses containing lighter weapons, medicine, food, and thousands of mattresses.
