A huge blaze broke out on Thursday at a gas-fired power station just outside Moscow with a plume of smoke and flames surging 50 meters into the sky, Russian television showed.
The fire at Power Station No. 27 broke out around 11:00 am on Thursday.
The emergencies ministry said that at least five people were injured, while the health ministry said it was at least six.
An energy ministry official said in televised comments that the fire in the Mytishchi district north of Moscow was caused by gas, after an initial statement that it broke out in an oil cistern.
The smoke and flames were visible from the capital and the emergencies ministry said that the fire blazed over an area of 200 square meters.
The emergency services sent in helicopters and fire-fighting trains to tackle the blaze.
Moscow Mayor Sergei Sobyanin wrote on Twitter that the city was sending 50 of its fire engines to the power station. The authorities closed a nearby highway leading to Moscow.
The power station was built at the end of the Soviet era. It supplies part of Moscow and the Moscow region with electricity.
The energy ministry said electricity supplies to the public would not be affected.