The Air Force released video that appears to show Russian fighter jets harassing several U.S. drones in Syria on Wednesday, June 5. The video shows a Russian SU-35 fighter closing in on a U.S. MQ-9 Reaper drone, and later showed a number of the so-called parachute flares moving into the drone’s flight path.

“Additionally, one Russian pilot positioned their aircraft in front of an MQ-9 and engaged afterburner, dynamically increasing speed and air pressure, which reduced the MQ-9 operator’s ability to safely operate the aircraft,” the Air Force said in an annotation on the video. “These events represent a new level of unprofessional and unsafe action by Russian air forces operating in Syria.”

Lt. Gen. Alex Grynkewich, commander of 9th Air Force in the Middle East, said the drones were on a mission against the Islamic State group Wednesday when the harassment began. He added the jet blast from the afterburner could’ve damaged the Reaper’s electronics, reducing the drone operator’s ability to safely operate the aircraft.

“Russian military aircraft engaged in unsafe and unprofessional behavior while interacting with U.S. aircraft in Syria,” Lt. Gen. Grynkewich said in a statement. “We urge Russian forces in Syria to cease this reckless behavior and adhere to the standards of behavior expected of a professional air force so we can resume our focus on the enduring defeat of ISIS.”

About 900 U.S. forces are deployed to Syria to work with the Kurdish-led Syrian Democratic Forces battling the Islamic State militants there. No other details about the drone mission were provided, and it’s not clear where over Syria the harassment took place.

Wednesday’s harassment of U.S. drones by Russian fighter jets is far from the only incident between the two countries in Syria in 2023. In March, the U.S. accused Russia of flying jets over U.S. bases in Syria every day. That same month, a Russian military aircraft forced a U.S. down over the Black Sea.