At least two people were missing and numerous others were treated for injuries on Saturday after blasts were reported at an explosives plant in the central Russian town of Dzerzhinsk, the Interfax and RIA news agencies reported.

The plant, founded in Soviet times and known as the Kristall scientific institute, is one of the country’s major developers of explosive technology for military and civilian use. It is part of Russia’s Rostec, a state conglomerate that has been hurt by Western sanctions over Russian policy toward Ukraine.

The cause of the explosions was not immediately known.

Some 22 people were injured, Interfax reported, citing a source. An official at the local health ministry said that most of the injured had fragment wounds.

A section of the facility in Dzerzhinsk, about 250 miles east of Moscow, was partially destroyed and a fire broke out where explosives and ammunition, including aerial bombs, were stored, Russian news agencies said.