Russian authorities evacuated more than 2,300 people from villages in the region of Ryazan on Wednesday and five people were taken to hospital after a blaze broke out at an ammunition depot, sending thick smoke belching into the air.
Munitions could be heard detonating at the depot in footage circulated on social media. A witness in one of the videos said shrapnel and ash was falling from the sky. Reuters could not immediately verify the videos.
The depot housed 110 storage facilities containing missiles and artillery munitions, and rounds could be heard exploding once every 5-10 seconds, the RIA news agency cited the emergency services as saying.
Six people were hurt and five of them taken to hospital, TASS news agency cited a source as saying.
A state of emergency was declared in the region, its governor said in comments carried by the RIA news agency.
The Emergencies Ministry said a motorway was being closed down and that at least 14 villages were evacuated within a five-kilometre radius of the depot 260 kilometres (162 miles) southeast of Moscow, the Interfax news agency reported.
Fires and explosions at ammunition depots have plagued the Russian army for years and drawn criticism of lax safety standards.