Washington CNN  — 

A Russian fighter jet acted in an “unsafe manner” during a Tuesday encounter with NATO aircraft, with the Russian jet almost cutting into the flight path of a NATO plane, forcing the alliance jet to maneuver to avoid a dangerous situation, a NATO military official tells CNN.

The incident occurred Tuesday when two Spanish F-18 fighter jets assigned to the NATO Baltic Air Policing mission were scrambled to identify a Russian Tu-214 transport aircraft that was being escorted by two Russian Su-27 fighter airplanes over the Baltic Sea, close to NATO member airspace.

The NATO official said the Russian fighters were flying without a flight plan and had their transponders switched off, behavior NATO officials say can put civilian and military aircraft operating in the area at risk.

The Russian news agency TASS reported that the Tu-214 was transporting Defense Minister Sergey Shoygu, who was flying to the Russian controlled exclave of Kaliningrad.

NATO officials said they had no official information as to who was aboard the aircraft.

Scrambling F-18s

“The Tu-214 airplane had a valid flight plan, did identify itself and responded to air traffic control. The two escorting Su-27 flew without a flight plan, their transponders were switched off and they did not talk to air traffic control,” a NATO military official told CNN, adding that the F-18s were scrambled from Šiauliai Air Base in Lithuania “in order to assess the situation.”

Currently F-18 fighters from Spain, JAS-39 Gripen fighter jets from Hungary, and Typhoon jets from the UK are participating in NATO’s long-standing Baltic Air Policing mission.

NATO frequently scrambles jets to intercept aircraft that fly in close proximity to NATO airspace without filing a flight plan, without having turned on their compulsory transponder or without communicating with air traffic control.

The Russian news service TASS said that one of the Russian fighters had forced the NATO approaching aircraft to leave the area, with Shoygu’s press secretary posting a video of the encounter on social media.

‘Unsafe manner’

NATO accused one of the Russian jets of acting in an “unsafe manner” during the incident.

“Once the (Russian) planes’ intention was assessed, the two F-18 fighter aircraft turned left to move away from the intercepted aircraft. Shortly before, one of the Russian Su-27 fighters also turned left to almost cut into the flight path of one of the F-18s in an unsafe manner,” the NATO official said.

“Due to the quick and professional reaction of the F-18 pilot, a potentially dangerous situation for both airplanes was avoided,” the official added.

“Breaking away from the intercepted aircraft upon successful identification is a normal procedure for aircraft flying under NATO authorities. Pilots flying during NATO missions adopt a de-escalatory stance to prevent misunderstandings,” the NATO military official said.