An explosion in the Russian city of Dzerzhinsk has left 38 people injured, local media report.
According to a source quoted by Interfax news agency, the factory used to produce and store high-explosive bombs.
The JSC Crystal Research Institute has now been completely destroyed.
A factory official said they were evacuated.
Images posted on social media appearing to be a huge mushroom cloud billowing out over the blast area.
A spokesman for the local emergency ministry told Russian news agency that four of the 38 injured people were in a "serious condition," but there were no deaths.
Earlier, a spokeswoman for the local health ministry said that most victims were suffering from "mild and moderate wounds." severity ".
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Officials said there was a "technical explosion" in one of the workshops, which caused a fire of around 1
Last April three people died in another factory blast in Dzerzhinsk, which is believed to be one of the world's most polluted cities.