The US Air Force has released video said to show a Russian jet intercepting an American drone and dumping fuel on it over the Black Sea.

It said two Russian Su-27 jets intercepted the MQ-9 Reaper on Tuesday before one hit its propeller, forcing it to crash the drone in the ocean.

Retired air vice-marshal Sean Bell told Sky News the video shows the Russian plane “almost certainly trying to dump fuel over the engine” before it “clips the propeller” as it passes.

The MQ-9 is remotely piloted and used for surveillance and attack missions

American officials said the jet was flown in a “reckless, environmentally unsound and unprofessional manner”.

Moscow has denied the jets behaved dangerously and said they did not come into contact with the drone, claiming it crashed due to “sharp manoeuvring”.

Pic: U.S. European Command/Reuters
The video was shot from an onboard camera. Pic: U.S. European Command/Reuters

It said the Reaper was flying towards the Russian border with its transponders – wireless communication devices – turned off.

Defence minister Sergei Shoigu accused the US of ignoring flight restrictions imposed by Russia due to the Ukraine war.

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America has insisted the drone was in international airspace.

The incident has shown the increasing risk of confrontation between the superpowers and prompted the first calls since October between their top commanders and defence secretaries.