ISTANBUL, April 27 (Xinhua) -- A Russian warship sank after hitting a cargo ship in the Black Sea on Thursday due to heavy fog, but all were rescued, Turkish media said.

The incident occurred off the coast of Kilyos in Istanbul, not far from the Bosporus Strait, where the Russian warship crashed into a cargo ship and sank later, Turkish press reports said.

Initial reports said 15 troops went missing, but the Turkish coast guard confirmed later on its website that all 78 Russians onboard were rescued.

The freighter, which departed from Romania and was heading to Jordan, was carrying 17 crew and 8,800 sheep and was only slightly damaged, the reports said. The Turkish coast guard said the ship was flying a Togo flag.

Turkey's NTV said the Russian ship, named Liman, sank in the collision believed to be caused by heavy fog in the area.

The Turksih military sent a search and rescue plane to the area following a call for help from the Russians, and the conditions of the Russian crew are good, NTV said.

Turkish Prime Minister Binali Yildirim has called his Russian counterpart to express his sorrow, press reports said.