The US military said a Russian fighter plane clipped the propeller of one its spy drones and made it crash into the Black Sea on Tuesday in the first such direct encounter between the two world powers since Russia invaded Ukraine over a year ago.

The Russian defence ministry offered a different account and Moscow's ambassador to Washington said his country viewed the incident involving a US MQ-9 drone and Russian Su-27 fighter jet as a provocation.

The United States conducts regular surveillance flights in the region and has supported Ukraine with tens of billions of dollars in military aid, although it has not become directly engaged in the war.

Russia's defence ministry denied that its aircraft had come into contact with the unmanned aerial vehicle (UAV), which it said had crashed after "sharp manoeuvring". It said the drone had been detected near the Crimea peninsula, which Moscow annexed from Ukraine in 2014.

"The Russian fighters did not use their onboard weapons, did not come into contact with the UAV and returned safely to their home airfield," the defence ministry said.