In a dangerously close encounter, a Russian fighter jet zipped past a U.S. Air Force reconnaissance aircraft in international airspace over the Black Sea late last month, a report said Thursday, citing several U.S. military officials. The two planes reportedly came within 10 feet of each other while flying at high speed.

The Russian jet flew next to the U.S. spy plane at the same altitude, broke off and then followed the American aircraft before leaving the area in the May 30 incident, CNN reported, adding that U.S. military officials count not confirm whether the government has taken any diplomatic steps to address the incident.

A similar incident took place in April when a U.S. RC-135U aircraft flying a routine flight over the Baltic Sea was intercepted by a Russian SU-27 Flanker. The incident, which occurred in international airspace north of Poland, was reportedly described by Pentagon officials as “unsafe and unprofessional” because of the “aggressive maneuvers” performed by the Russian pilot “in close proximity to their aircraft and its high rate of speed.”

Earlier this month, the U.S. Navy released a video showing a Russian Su-24 aircraft flying past the U.S. guided missile destroyer USS Ross in the Black Sea on May 30.

“USS Ross (DDG 71) observes the overflight by a Russian SU 24 aircraft while both were operating in international waters and airspace,” U.S. Naval Forces wrote in the description of the video. “Ross continued on her mission after observing the aircraft return to base. At no time did Ross act aggressively nor did she deviate from her planned operations.”

On Monday, the U.S. Navy released a video, showing two unidentified jets flying over a NATO maritime exercise, which comprised of dozens of ships and aircraft, in international waters in the Baltic Sea.

According to a recent report by the European Leadership Network, the Russian jets have increased harassment of U.S. and NATO reconnaissance aircraft with close overflights of warships and “mock bombing raid” missions.

“These events add up to a highly disturbing picture of violations of national airspace, emergency scrambles, narrowly avoided mid-air collisions, close encounters at sea, simulated attack runs and other dangerous actions happening on a regular basis over a very wide geographical area,” the report said.