Russia's military denied one of its jets made aggressive maneuvers during an incident with a U.S Air Force reconnaissance plane flying over the Baltic Sea.
The U.S. military said the Russian SU-27 jet had flown in "an unsafe and unprofessional manner," getting within 15 meters of the U.S. RC-135 aircraft Thursday.
Russian defense ministry spokesman Igor Konashenkov said Russia had to scramble to dispatch an aircraft after detecting an unidentified aerial target flying at high speeds towards its border.
He said when the American aircraft made visual contact with the Russian jet, the reconnaissance plan changed course, flying away from the border.
A statement from the U.S. European Command on Saturday said the incident occurred in international airspace and at no time did the American plane cross into Russian territory.
Days ago, Russian fighter jets flew very close to the USS Donald Cook in international waters in the Baltic Sea.
The crew aboard the warship was dumbfounded to see the apparently unarmed SU-24 planes fly as close as nine meters from the destroyer, close enough to create a wake in the water.
Russia's Defense Ministry denied the action was provocative, saying the planes were conducting test flights and only observed the Donald Cook before turning away, "in observance of all safety measures."
A Pentagon official described the Russian flights as simulated attack passes. He said sailors on the Donald Cook attempted to reach the Russian planes by radio, but got no response.
Some military analysts say they believe the Russian maneuver may have come out of the Kremlin's resentment of U.S. forces operating so close to Russian territory.
NATO has bolstered its military presence in Eastern Europe as a response to the Russian annexation of Crimea in Ukraine in 2014.