Updated 3/14/23 at 3:17 pm ET with comments from DoD spokesman Brig. Gen. Patrick Ryder and Commandant of the Marine Corps Gen. David Berger.

WASHINGTON — Russian Su-27 fighter jets were harassing a US MQ-9 drone before they bumped the American aircraft mid-flight, causing it to crash into the Black Sea today, according to a US European Command statement.

The incident happened over international waters south of Crimea, according to a source with knowledge of the event. The source added that Russian jets have frequently harassed MQ-9s operating in the region, without any real incident since the start of Russia’s invasion of Ukraine, until now.

According to EUCOM, one of the Russian jets struck the propeller of the MQ-9, causing enough damage that operators decided to bring the drone down in the water rather than try to return it back to base. (While EUCOM did not state where the drone is operating from, it is likely out of Romania.) The US has reportedly summoned the Russian ambassador to lodge a complaint over the incident

“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,” the EUCOM statement continued.

“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 Air Force Gen. James Hecker, commander, US Air Forces Europe and Air Forces Africa, in the statement. “In fact, this unsafe and unprofessional act by the Russians nearly caused both aircraft to crash.”

Speaking to reporters at the Pentagon, DoD spokesman Brig. Gen. Patrick Ryder said that the Russians were harassing the drone for roughly 30 to 40 minutes before one got too close and “essentially ran into the MQ-9.” The US did track the Russian jets landing safely, but “we assess it likely caused some damage” to the Su-27 that hit the MQ-9.

The source with knowledge of the incident told Breaking Defense the initial indications are that it was an accidental impact by the Russian pilot. Ryder did not directly answer when asked if the US believes it was an accident, saying, “We are continuing to assess exactly what happened, but based on the actions of the Russian pilots, it was clear it was unsafe, unprofessional and I think the actions speak for themselves.”

It is likely the Russians will try to recover the American drone, although how successful they will be is an open question. Ryder also would not comment on US or allied assets in the region that could attempt to recover the aircraft, but did state that “to my knowledge at this point and time the Russians have not recovered” it.

The incident is not likely to reassure those who are concerned that a mistake mid-air between the US and other militaries could lead to an accidental conflict. Speaking at the National Press Club just as the EUCOM statement became public, Gen. David Berger, the Commandant of the Marine Corps, appeared to count himself in that group

“This is probably my biggest worry, both there [the Black Sea region] and the Pacific, is that an aggressive Russia or China pilot or vessel captain or something gets too close — doesn’t realize where they are, causes a collision and it’s two in the morning and we are trying to unpack this as fast as we can,” Berger said, stressing that it’s not just a concern with Russia.

“Even more challenging because right now [with China] — normally we would have communications with the PLA and their military. It doesn’t exist right now. They won’t communicate with us. So the normal sort of many channels that you have to kind of quickly defuse something — they’re not — they’re not gone but they’re suspended right now. So I’m worried that something will happen at two in the morning and we can’t talk to our counterparts to say, ‘What the heck was that?’”

Justin Katz in Washington contributed to this report.