Out of approximately 60 reported sightings in 11 countries from August to November, only four — in Poland, Romania and Moldova — involved confirmed Russian drones that were either shot down by NATO aircraft or identified through recovered debris, the newspaper reported.

Trouw, which reviewed dozens of incidents using the platform Dronewatch, said the origin of 40 reported sightings could not be verified at all, with no visual, radar or debris evidence to confirm a drone’s presence.

At least 14 reports were later attributed to ordinary aircraft, helicopters, ships or even stars. A map compiled by Trouw showed three hobby or tourist drones and 11 other objects that were ultimately deemed not to be drones.