CNN
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A Russian fighter jet forced down a US Air Force drone over the Black Sea on Tuesday after damaging the propeller of the American MQ-9 Reaper drone, according to a US official familiar with the incident.

The Reaper drone and two SU-27 Flanker jets were operating over international waters over the Black Sea when one of the Russian jets intentionally flew in front of and dumped fuel in front of the unmanned drone, according to the official. One of the jets then damaged the propeller of the Reaper, which is mounted on the rear of the drone, the official said. The damage to the propeller forced the US to bring down the Reaper in international waters in the Black Sea.

The US Air Force issued a statement accusing the Russian aircraft of acting in a “reckless, environmentally unsound and unprofessional manner.”

“At approximately 7:03 AM (CET), one of the Russian Su-27 aircraft struck the propeller of the MQ-9, causing U.S. forces to have to bring the MQ-9 down in international waters. Several times before the collision, the Su-27s dumped fuel on and flew in front of the MQ-9 in a reckless, environmentally unsound and unprofessional manner. This incident demonstrates a lack of competence in addition to being unsafe and unprofessional,” US Air Force Gen. James B.Hecker, commander, U.S. Air Forces Europe and Air Forces Africa said in the statement.

Russian and US aircraft have operated over the Black Sea during the course of the war, but this is the first known such interaction, a potentially dangerous escalation at a critical time in the fighting.

The US has been operating Reaper drones over the Black Sea since before the beginning of the war, using the spy drones to monitor the area. Reaper drones can fly as high as 50,000 feet, according to the Air Force, and they have sensors and capabilities to gather intelligence and perform reconnaissance for extended periods of time, making it an ideal platform to track movements on the battlefield and in the Black Sea.

This story is breaking and will be updated.