The ministry said radiation levels were normal but the city of Severodvinsk registered a "brief spike" in levels.
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Local people were reportedly urged to take precautions against radiation. No increase in ambulance call-outs was recorded, the administration added.
A woman in Severodvinsk named only Alina told Russian news site lenta.ru: "I work in the hospital where they're bringing the injured.
"They advise everyone to close their windows and drink iodine, 44 drops per glass of water.
Children in local kindergartens were taken indoors after reports of the blast and parents were advised not to take them outside in the evening, other residents were quoted as saying.
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"During testing of a liquid jet engine an explosion and combustion of the product occurred," the ministry said in a statement. "There have been no harmful chemicals released into the atmosphere, the radiation levels are normal."