A Russian An-72 transport plane entered Estonian airspace without permission on Thursday noon at 12:10.
The intrusion took place near Vaindloo, Estonia's northernmost island, and lasted for less than a minute.
The plane's transponder was switched on and it had a flight plan, which specified a route in international airspace. However, the plane had no radio contact with Estonian air traffic controllers at the time of the intrusion, Estonian Defense Forces said.
The Ministry of Foreign Affairs has asked the Russian Ambassador in Tallinn for an explanation and issued a démarche over the incident.
This was the third time this year that a Russian army plane violated Estonian airspace.
ERR recently reported that the Russian military aircraft have also made over 260 so-called "blind" flights near Estonia in 2015, forcing NATO fighter jets to scramble from Ämari to intercept and identify the aircraft that are invisible to most radars used by civil air traffic control.
Editor: M. Oll