A Russian nuclear submarine is lying crippled on the sea bottom in Arctic waters.
Officials say the submarine's engine failed and it sank during a routine exercise.
A Russian spokesman says there are no radiation leaks. As Bill Gasperini reports from Moscow, rescue operations have begun. Rescue vessels have arrived at the scene and have established radio contact with the crew of the stricken submarine, which is lying on the bottom of the Barents Sea in the Russian Arctic. A Russian Navy official says there are no nuclear weapons on board the sub, which was taking part in routine exercises when it began to malfunction. The technical problems forced the sub to descend to the sea floor.