Russia's Defense Ministry said a fire triggered the explosions at a storage facility for gunpowder charges near the city of Achinsk in eastern Siberia's Krasnoyarsk region.
Authorities declared a state of emergency in the region and ordered the evacuation of residents of several districts in Achinsk, as well as towns and villages within 20 kilometers (12.4 miles) of the depot.
Regional Gov. Alexander Uss said 6,000 people were being evacuated under the order.
Air traffic was suspended within 30 kilometers (18.6 miles) of the munitions site. Videos posted by local residents showed powerful explosions sending plumes of black smoke high into the sky.
Ammunition depot explosions are not unusual in Russia. After the most recent incident in May 2018, a fire raged for almost a week before water drops from military aircraft and helicopters helped put out the blaze.