Seven people died and nine others were missing after a fire on Friday at a factory southeast of Moscow that produces industrial explosives as well as armaments.
Amateur video footage on Russian social media showed rows of fire trucks with burning debris in a wooded area by the factory in the village of Lesnoye, 300 kilometres (180 miles) from Moscow.
"Seventeen people were injured, of them seven died, one has been hospitalised and the fate of nine people remains unknown," the emergencies ministry said in a statement.
Earlier it said the fire could have broken out as a result of "violations of the technological processes and safety measures" at the PGUP Elastic factory in the Ryazan region.
The plant says on its website that it produces industrial explosives for civilian use but also ammunition for the defence sector as well as gas generators for submarines.
The emergencies ministry said it first received a report that a fire had broken out at the plant at 08:22 local time.
The head of the local administration earlier told the TASS news agency that the 17 people were inside the plant's workshop at the time of the fire.
The ministry said it had deployed more than 170 rescuers to the area.
Concerns over safety standards
The official toll from the incident was expected to rise with a source telling the Interfax news agency that 16 people had died.
Accidental fires are common in Russia, where hundreds of blazes are recorded each year due to ageing and dilapidated infrastructure and non-compliance with safety standards that are often lax.
In Russia's worst fire disaster in recent memory, an inferno at a shopping centre in the Siberian city of Kemerovo in 2018 left 64 people dead, including 41 children.