Finnish airport operator Finavia said airports in Finland are functioning as usual.

Airports in several countries, such as in Denmark and Norway, have recently reported unauthorised drone activity which has led to flight disruptions or even the temporary closure of some airports.

“Airports use various methods to detect drones, but the details, and any possible sightings, are security sensitive and cannot be disclosed,” Finavia told Yle in an email.

Finavia said it works closely with the authorities and that any cases of drones being flown in violation of regulations are always referred to the police.

Drone flights near airports are banned without special permission, and Finland’s transport regulator, Traficom, has set protective buffer zones around them.

The drones spotted over Denmark appear to be part of a coordinated operation, according to Iro Särkkä, a senior researcher at the Finnish Institute of International Affairs (FIIA). She said that while suspicion falls on Russia in the current geopolitical climate, there is, as yet, no firm evidence of Russian involvement.

Earlier this month, Poland shot down Russian drones after an airspace violation.