A NATO flotilla arrived in the Black Sea on Wednesday to train with ships from the Bulgarian, Romanian and Turkish navies, the U.S.-led Western alliance said.
Tensions in the Black Sea region are running high because of the separatist conflict in eastern Ukraine and Russia's annexation of the country's Crimea peninsula last year.
"NATO regularly deploys ships to the Black Sea for maritime awareness and training. This scheduled deployment, given Russia's continued assertiveness, carries an additional message of reassurance to allies in the region," a NATO official said.
The multinational naval rapid reaction force commanded by U.S. Rear Admiral Brad Williamson consists of flagship USS Vicksburg, a guided missile cruiser, and five other ships.
The training will include simulated anti-air and anti-submarine warfare exercises, as well as simulated small boat attacks and basic ship handling maneuvers.