A Russian fighter jet collided with a U.S. drone over the Black Sea, according to a statement by the U.S. military on Tuesday.

The fighter jet struck the propeller of the U.S. military "reaper" surveillance drone, forcing the U.S. to bring it down, the military said.

"Our MQ-9 aircraft was conducting routine operations in international airspace when it was intercepted and hit by a Russian aircraft, resulting in a crash and complete loss of the MQ-9," said U.S. Air Force General James Hecker, commander of U.S. Air Forces Europe and Air Forces Africa.

"In fact, this unsafe and unprofessional act by the Russians nearly caused both aircraft to crash."

Russia's defense ministry said that its fighter jets did not come into contact with a U.S. drone that crashed into the Black Sea earlier, claiming instead that the drone crashed due to "sharp maneuvering."

"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 defense ministry said.

Russian intercepts over the Black Sea were common, US National Security Council spokesman John Kirby told journalists in Washington, but this one "is noteworthy because of how unsafe and unprofessional it was, indeed reckless that it was".

NATO diplomats in Brussels confirmed the incident but said they did not expect it to immediately escalate into a further confrontation.

A Western military source, speaking to AFP on condition of anonymity, said that diplomatic channels between Russia and the United States could help limit any fall-out.

"To my mind, diplomatic channels will mitigate this," the source said.

Russia's invasion of Ukraine in February last year has led to heightened fears of a direct confrontation between Moscow and the Western NATO military alliance, which has been arming Kyiv to help it defend itself.

News of a missile strike in eastern Poland in November last year briefly caused alarm before Western military sources concluded that it was a Ukrainian air defence missile that had malfunctioned, not a Russian one.