An explosion was heard on Tuesday morning at the Ural military-industrial plant in the city of Solikamsk, in central Russia, local media reported.
Photos published on social media show a mushroom of smoke rising above the plant, located in Russia’s Perm region.
Ural is one of Russia’s largest plants producing explosives for ammunition, as well as paint, rubber, and plastic products.
The Perm emergencies ministry said that a ‘bang’ had been heard at one of the plant’s buildings.
"No one was in the building at the time of the explosion. The explosion did not affect the company's operations," it said in a statement.
ChP Solikamsk, a local social media group, claimed the explosion and the column of smoke had resulted from a "technological flash", citing local emergency workers.
The explosion at the Ural plant "damaged nearby houses", local TV channel SolTV reported, adding there was a threat of another explosion.
The plant’s management and emergency officials convened an extraordinary meeting.
It was not immediately clear whether Ukraine bore any responsibility for the explosion, as Kyiv has vowed to undercut Moscow's military potential, including by striking Russian territory.