"The work of military divers began a few days after the incident. This work is continuing now. Depending on the weather, the work of the divers can last a week or two," the source said.
The Liman research ship collided last Thursday with a Togo-flagged vessel 40 kilometers (25 miles) from the Bosphorus Strait. The Russian vessel sunk after its hull was ruptured; all 78 crew members were rescued.
The source said four Russian Black Sea Fleet mooring and rescue ships are located in the vicinity of where the Liman had sunk.
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