This contradicts initial statements that there no injuries or damage occurred.
The press service for Russia's Investigative Committee said on September 17 that, as a result of the fire aboard the "Tomsk" submarine at a shipyard near the city of Vladivostok on September 16, the vessel "lost some of its functional characteristics."
The press service also said that 15 servicemen were being treated at a military hospital.
It did not provide any details about the injuries the sailors suffered or the extent of the damage to the submarine.
Officials continue to say the submarine's reactor was deactivated before the fire and posed no danger.