Washington: A Russian aircraft fired flares at the US drone over Syria and damaged its propeller, America's military said on Tuesday.

Lieutenant General Alex Grynkewich, the head of US Air Forces Central, in a statement, revealed that on Sunday, the Russian fighter aircraft flew dangerously close to a US MQ-9 drone on a defeat-ISIS mission, harassing it and deploying flares from a position directly overhead, with only a few metres of separation between aircraft.

"One of the Russian flares struck the US MQ-9, severely damaging its propeller. Fortunately, the MQ-9 crew was able to maintain flight and safely recover the aircraft to its home base," the head of US Air Forces Central said.

"The Russian fighter’s blatant disregard for flight safety detracts from our mission to ensure the enduring defeat of ISIS. We call upon the Russian forces in Syria to put an immediate end to this reckless, unprovoked, and unprofessional behaviour,” he added.

The Sunday incident is the latest in a series of encounters between Russian fighter jets and US aircraft flying over Syria.

A similar incident took place in March over the Black Sea, a Russian Su-27 fighter jet struck the same type of US drone, damaging its propellor and forcing it down in the water, reported CNN.

Last week, Chairman of the Joint Chiefs of Staff Gen. Mark Milley said US analysts are examining the potential reasons behind the uptick in aggressive Russian actions.

Some of the incidents over Syria have lasted as long as two hours, US officials said, according to CNN.

Earlier, on July 16, Russian military aircraft engaged a US aircraft in Syria in "an unsafe and unprofessional manner."

Grynkewich, the head of US Air Forces Central, in a statement dated July 18, said, "A US MC-12 was conducting operations in support of the Coalitions Defeat ISIS mission was closely approached by a Russian Su-35 against established norms and protocols, forcing the MC-12 to fly through its wake turbulence."

"This reduced the crew’s ability to safely operate the aircraft and put the four crewmembers’ lives at risk. These actions against a manned aircraft represent a new level of unsafe and unprofessional actions by Russian aircraft operating in Syria. We strongly urge Russian forces in Syria to cease reckless and threatening behaviour that could result in an accident and loss of life, and adhere to the standards of behaviour expected of a professional force,” he added.