U.S. officials described the intercept by the SU-27 jet on Wednesday as "dangerous and unprofessional", the BBC reported.
Russia's defense ministry said the U.S. plane had been approaching Russian territory and the SU-27 pilots had adhered to international rules.
Russia is currently carrying out military exercises in the Black Sea.
Pentagon spokesman Capt. Jeff Davis said the U.S. Navy P-8A Poseidon aircraft had been conducting routine operations in international airspace when the Russian fighter made the unsafe maneuver.
"These actions have the potential to unnecessarily escalate tensions, and could result in a miscalculation or accident," he said.