A Norwegian dive support ship arrived at the site of the sinking of the Kursk submarine, and divers prepared to start work to raise the wrecked vessel, news reports said.
The Kursk sank during a training exercise off northwestern Russia last August, killing all 118 crewmen. Russia plans to raise the submarine in a salvage operation lasting through mid-September.
The submarine, which has nuclear reactors and unexploded torpedoes aboard, lies on the sea floor under 356 feet of water.
Divers will examine the hull in the first phase of the operation, the Interfax news agency reported.