Footage of explosions at the Ulyanovsk arms depot
At least two people have been killed after a series of explosions and fires at a weapons depot in central Russia, officials say.
The blasts ripped through the defence ministry navy depot on the outskirts of Ulyanovsk when soldiers attempted to decommission munitions.
The officials later said that 43 people who were feared dead had been found safe in a bomb shelter near the site.
Some 3,000 people were evacuated from the surrounding area.
The depot is about 900km (550 miles) south-east of the capital Moscow.
Two fire-fighters died at the Arsenal 31 depot after the blasts and fires, Ulyanovsk Governor Sergei Morozov told the BBC.
Mr Morozov was earlier quoted in Russian media as saying that at least 10 people were taken to hospital.
The governor also told Russia's First Channel TV: "More than 40 people have been saved, including those who were reported missing."
He was referring to the 43 people who had been found safe and well in the bomb shelter.
Explosions at the depot continued into the night, with TV footage of the area showing intermittent blasts sending thick plumes of smoke high into the air. The blasts shattered windows of nearby homes.
The first explosion happened about 1600 local time (1300 GMT) while ammunition was being disposed of at the site. The blast set off a series of explosions and also started fires.
"There was a loud bang, then there was silence and then there were explosions, explosions, explosions, like fireworks on New Year," local resident Igor Komandin told First Channel.
Fire-fighters at the scene were battling the blazes several hours after it started.
A large exclusion zone has been set up around the depot.
The Federal Security Service advised Ulyanovsk residents to buy gauze masks and stock up on drinking water, but added that the situation was under control.
Officials said artillery shells and torpedoes were kept at the arsenal, adding that a nearby chemicals weapons depot was not in any danger.
A criminal investigation into the accident is now under way.
Ulyanovsk sits beside the Volga river and is the birthplace of Bolshevik leader Vladimir Lenin.