A Russian naval task force is reportedly heading from the Mediterranean to the Black Sea for maritime drills, amid a surge of tensions between Russia and the West over Ukraine.
The state-run TASS news agency quoted Russia's Defense Ministry as saying on Tuesday that six Russian warships had started transiting the Bosporus and Dardanelles straits in Turkey.
The vessels include the Korolev, the Minsk and the Kaliningrad, which are set to navigate the Bosphorus on Tuesday, while the Pyotr Morgunov, the Georgy Pobedonosets and the Olenegorsky Gornyak are expected to pass on Wednesday.
"Currently, the crews of the large amphibious assault ships Korolyov, Minsk and Kaliningrad are in the Dardanelles Strait. The amphibious assault ships Pyotr Morgunov, Georgy Pobedonosets and Olenegorsky Gornyak will pass through the Black Sea straits during the next day," the Russian Defense Ministry said.
The Russian military announced last month its navy forces would stage a sweeping set of exercises involving all its fleets in January and February, from the Pacific to the Atlantic.
Russia's naval task force completed its transit around Europe earlier in the month and arrived at the Russian navy's logistics facility in the Syrian port of Tartus on the Mediterranean coast to replenish its fuel and food supplies.
The naval maneuvers, focusing on measures to protect Russia's national interests and counter military threats to the country, are set to bring together over 140 warships and support vessels, more than 60 aircraft, 1,000 items of military hardware and about 10,000 troops.
Relations between Russia and the West have hit a new low in recent weeks. The United States, its NATO allies, and Ukraine have accused Russia of amassing troops near Ukraine's border for a possible invasion. Moscow rejects the allegation and insists that deployments are defensive in nature.
The US military has placed 8,500 troops on heightened alert to prepare for deployment in Eastern Europe and bolster the NATO presence in the region. The US State Department has also approved shipments of US-made missiles and other weapons from NATO allies Lithuania, Latvia, and Estonia to Ukraine.
After a diplomatic shuttle between Moscow and Kiev, French President Emmanuel Macron said the resolution of the Ukraine crisis would "take time," adding that it was imperative to "find ways of bringing viewpoints together and lowering the tension."
Russia has demanded legally binding guarantees from NATO that it will halt its eastward expansion and return to its 1997 borders. Moscow also demanded that the military alliance never admit Ukraine as a member.
However, the Kremlin said Russia's main security demands had not been taken into account by the US after Washington delivered written replies to Moscow.