![F-16 F-16](https://lithuaniatribune.com/wp-content/uploads/2019/04/7991273-678x381.jpg)
All four Russian aircraft were transport airplanes flying with pre-filed flight plans, maintained contact with flight controllers but had their onboard transponders off. They were flying from mainland Russia to the Russian Kaliningrad region and back.
The NATO air-policing mission is conducted from Lithuania and Estonia.