A powerful explosion at a fireworks factory killed at least two people in the town Gatchina, some 40 km south of St. Petersburg, on Friday.
The blast occurred at the Avangard plant, one of the largest manufacturers of pyrotechnics in Russia.
According to Russia's Ministry of Emergency Situations (EMERCOM), two bodies were found under the debris with two other people suffering injuries. The ministry also said that the explosion is not thought to have been caused deliberately. The cause of the incident and information on those missing is being verified.