US European Command said two Russian Su-27 fighters intercepted the unmanned MQ-9 Reaper over Black Sea international waters and one clipped its propeller.
"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," it said.
The statement confirmed an earlier report by AFP of an incident involving a US-made drone.
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 would be activated.
"To my mind, diplomatic channels will mitigate this," the source said.
The United States uses MQ-9 Reapers for both surveillance and strikes, and has long operated over the Black Sea keeping an eye on Russian naval forces.
The situation in the region has become only become more tense in the past 12 months since Russia's full-scale invasion of Western-backed Ukraine.
"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 US Air Force General James Hecker, commander of US Air Forces Europe and Air Forces Africa.
"In fact, this unsafe and unprofessional act by the Russians nearly caused both aircraft to crash."
"US and allied aircraft will continue to operate in international airspace and we call on the Russians to conduct themselves professionally and safely," he added.
Several US Reapers have been lost in recent years, including to hostile fire.
One was shot down in 2019 over Yemen with a surface-to-air missile fired by Huthi rebels, the US Central Command said at the time.
According to media reports, a US MQ-9 crashed in Libya in 2022, while another went down during a training exercise in Romania earlier in the same year.
Reapers can be armed with Hellfire missiles as well as laser-guided bombs and can fly for more than 1,100 miles at altitudes of up to 15,000 meters according to the US Air Force.
US Drone, Russian Fighter Collide, Crash
![FILE: an MQ-9 Reaper unmanned aerial vehicle (UAV or drone) flying over the Nevada Test and Training Range on January 14, 2020.](https://gdb.voanews.com/06a20000-0aff-0242-3148-08db04acfeff_w250_r1_s.jpg)
BRUSSELS - A Russian fighter jet on Tuesday dumped fuel on an American drone over the Black Sea then collided with it, causing the drone to crash, the US military said.