A Russian fighter jet made an “unsafe” intercept of a U.S. reconnaissance aircraft over the Black Sea on Wednesday, the Pentagon said, claiming that the interception was carried out in a “dangerous and unprofessional” manner as the Russian plane flew within about 10 feet of the U.S. aircraft.

According to Pentagon spokesman Jeff Davis, the U.S. Navy P-8A Poseidon aircraft was conducting routine operations in international airspace when the Russian SU-27 jet made the risky maneuver. Russia’s defense ministry, meanwhile, said that the U.S. spy plane tried to approach the Russian border, and the SU-27 jet was scrambled in response with adherence to international rules, BBC reported.

“These actions have the potential to unnecessarily escalate tensions, and could result in a miscalculation or accident,” Davis reportedly said.

However, Russian officials said that the U.S. plane was intercepted because it was heading toward the Russian territory with its transponders switched off. When the Russian jet approached the U.S. spy plane to visually identify them, it changed direction and flew away from the border, Russia’s RT.com reported.

P-8A_Poseidon A P-8A Poseidon assigned to the Bureau of Air Test and Evaluation Squadron (VX) 20 flies over the Chesapeake Bay.

“They're up there for 12 hours and there are lots of interactions. But only one of the incidents was what the pilot determined was unsafe,” an anonymous U.S. official told Reuters.

Wednesday’s incident is likely to spark more tension between the U.S. and Russia whose relations have been strained since the latter annexed Crimea from Ukraine in 2014. The latest incident also comes as the U.S. Secretary of State John Kerry and Russian Foreign Minister Sergey Lavrov are expected to meet Thursday to discuss the ongoing conflict in Syria.

In April, the U.S claimed that Russian warplanes had confronted one of its reconnaissance aircraft over the Baltic Sea while Russia said at the time that the American jet had turned off its transponder signal.

In July, NATO leaders agreed to deploy four multinational battalions to the Baltic states and Poland on a rotational basis against Russian aggression. Moscow also responded to the move saying that NATO’s buildup in those regions would be inevitably followed by a “military technical” response.