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

“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 overseas the U.S. Air Force in the region, said in a statement.