A Russian Su-27 fighter jet intercepted and struck the propeller of a U.S. military MQ-9 “Reaper” surveillance drone on Tuesday, causing it to crash into the Black Sea in an incident condemned as “unsafe” by the U.S. military.

Two Russian Su-27 jets carried out the intercept of the American spy drone, and one of them collided with it at 7:03 a.m. (6:03 GMT). Several times before the collision, the Russian fighter jets dumped fuel on the MQ-9 and carried out unsafe maneuvers in front of it, the U.S. military said in a statement.

“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,” U.S. Air Force General James Hecker, who oversees the U.S. Air Force in the region, said.

“In fact, this unsafe and unprofessional act by the Russians nearly caused both aircraft to crash,” he condemned.

The U.S. military said the incident was in line with a pattern of dangerous behavior displayed by Russian pilots operating near aircraft flown by the U.S. and its allies, including over the Black Sea. The Black Sea lies between Europe and Asia and is bordered by Russia and Ukraine along with other countries.

John Kirby, spokesman for the White House, said that president Joe Biden was briefed on Tuesday about the incident.

“The State Department will be speaking directly with their Russian counterparts, and expressing our concerns over this unsafe and unprofessional intercept,” he added.