Two buildings at the plant were destroyed and pyrotechnics began detonating at the site, according to the regional governor, Mikhail Yevrayev, who reported the fire at the facility in Pereslavl-Zalessky district. The emergency services received the alarm at 16:06, TASS reported, citing operational services.
Fifteen people were at the factory when the fire broke out, TASS said. The Telegram channel 112, which is close to the security services, also reported that 15 people were in the workshop.
About 100 firefighters and 40 pieces of equipment were deployed to extinguish the blaze.
Children and teachers were evacuated from the nearby Center for Additional Education and the Kubrinsky Child Development Center. The Telegram channel Ostorozhno, Novosti reported that 42 people were also evacuated from a kindergarten and a creative arts center, including 40 children.
Investigators opened a criminal case over a violation of industrial safety requirements at hazardous production facilities that resulted in the deaths of people, TASS reported.
An operational headquarters was set up in the region and a decision on declaring a state of emergency is being prepared. The cause of the fire is still being established.
Sources gave differing casualty figures at different stages: five deaths were reported first, then ten, according to TASS citing the Ministry of Emergency Situations, and later 13, according to The Insider. Accounts of how many people were at the plant also varied, with TASS and 112 both citing 15.