"To intercept the target, an Su-27 fighter from the Air Defence Forces of the Southern Military District was scrambled", the statement says.
After the US Navy reconnaissance aircraft turned away from Russia's border, the Russian fighter returned to its home airfield.
Earlier in the day, Russian airspace control devices detected an air target approaching Russia's state border over neutral waters in the Black Sea.
The entire flight of the Russian aircraft was conducted in strict accordance with international rules for the use of airspace. Violations of the Russian state border were not allowed, the NDCC added.
About 2,000 servicemen from nine countries, more than 20 warships, as well as aircraft and helicopters, participated in the naval drills. This year, the event also included Bulgaria, France, Georgia, Norway, Romania, Spain, and Turkey.