"As result of the fire that hit the Moskva missile cruiser, the ammunition has detonated. The ship has been seriously damaged," the ministry said in a statement.
The statement added that all the crew members had been safely evacuated, causes of the fire are being investigated.
Other details of the incident, as well as the cause of the fire, are not given at the moment.
In early February, the cruiser conducted exercises to defend the Crimean peninsula in the Black Sea.
The ship, whose initial name was "Slava," was laid down in 1976 in Nikolaev and commissioned in 1983.