The radiation on the submarine is normal as its nuclear reactor is working at normal status, said Igor Dygalo, an aide to the commander-in-chief of the Russian Pacific Fleet.
Among the killed are workers of a shipyard and military servicemen, he said.
The submarine is sailing to a temporary base in Russia's far east Primorye territory with the escorting of an anti-submarine warship and a rescue vessel to evacuate another 21 injured people, Dygalo said.
There were 208 people aboard the submarine during the accident and 81 of them were military servicemen.
Russian President Dmitry Medvedev has ordered the defense minister to probe into the accident and provide all the necessary assistance to the families of the killed, said the Kremlin.
The last major tragedy on Russian nuclear submarine occurred on Aug. 12, 2000, when the Kursk sank during a military exercise in the Barents Sea after an explosion ripped through the vessel. All 118 sailors perished.
The latest similar accident was reported in September, 2006, when two servicemen were killed and one injured in a fire onboard a Russian nuclear submarine.
(CCTV November 10, 2008)