Denmark reported that drones flying over several airports, including Aalborg and Billund, were likely operated by a “professional actor” in a “systematic” hybrid attack, though there is no evidence of Russian involvement.

The incursions forced temporary closures and flight diversions, posing risks to aircraft during take-off and landing.

Authorities said the drones were launched locally and were not shot down due to safety concerns for nearby populations.

The incidents come amid heightened European alert after suspected Russian drones and aircraft entered NATO airspace in Estonia, Poland, Romania, Germany, and Sweden, the BBC has reported.

Danish officials and EU leaders are discussing enhanced drone defense measures, while NATO has vowed to use all necessary tools to protect member states’ airspace.