The shutdown occurred on Friday, the report said, but was not reported until Tuesday.

The station which has only one functioning nuclear reactor is located in the town of Volgodonsk in the southern Rostov region.

Nuclear energy officials were not immediately able to determine what caused the problem, with ITAR-TASS reporting that an investigation was being conducted at the scene.

There was no immediate information about any possible radiation leaks during the accident, but the report said the power supplies were not affected in the region.

WAR.WIRE