A US surveillance aircraft was twice ‘buzzed’ by a Russian fighter over the Black Sea in what the Pentagon says was an ‘unsafe and unprofessional’ manoeuvre.

The EP-3 Aries aircraft was monitoring activity in Europe’s Black Sea when it was intercepted by what US officials describe as an ‘armed’ Russian Su-27 fighter jet.

“This interaction was determined to be unsafe due to the SU-27 conducting a high speed pass directly in front of the mission aircraft, which put our pilots and crew at risk,” a statement from the US European 6th Fleet reads.

The Russian warplane reportedly closed the distance with the large Aries before activating its afterburner — where fuel is dumped into the exhaust plume for added thrust. It then accelerated into a banking turn, directing the turbulence generated by its engines at the US aircraft.

“The crew of the EP-3 reported turbulence following the first interaction, and vibrations from the second,” the US statement reads. “The duration of the intercept was approximately 25 minutes.”

US military officials have not said how close the Russian jet actually was.

“While the Russian military is within its right to exercise within international airspace, this interaction was irresponsible. We expect them to behave within international standards set to ensure safety and to prevent incidents … unsafe actions increase the risk of miscalculation and potential for midair collisions.”

The Navy EP-3 was based in Souda Bay, Greece. US officials say the aircraft was flying with its navigation transponder announcing its position, but neither the Russian pilot nor ground control operatives attempted to make contact.

Russia’s embassy in the US issued a statement insisting its fighter had “followed all necessary safety procedures”.

“The Su-27 jet’s crew reported identifying the #US EP-3 Aries spy plane and accompanied it, preventing a violation of Russian airspace and followed all necessary safety procedures.”

A similar incident happened in January. In that case, an Su-27 ‘buzzed’ another EP-3 Aries — passing within just 1.5m. Again, the crew of the Aries had to endure the violent turbulence of the jet engine ‘wash’.

At the time, the US State Department accused the Russians of “flagrantly violating existing agreements and international law.”