Frederiksen said Danish authorities had yet to identify “who is behind the hybrid attacks against our airports and other critical infrastructure” but hinted the Kremlin was responsible.

“We can at least state that there is primarily one country that poses a threat to Europe’s security — and that is Russia,” she said.

Europe has been rattled by a series of airspace incursions involving Russian jets and drones in recent weeks. Estonia and Poland convened NATO members for urgent talks after accusing Russia of violating their airspace in separate incidents.

Moscow has denied responsibility for the Estonian incursion and said the Polish incident, which saw a swarm of drones cross into Polish airspace, was an accident.

Just hours after Frederiksen’s address, Aalborg Airport in the country’s north was briefly closed for the second night in a row due to a suspected drone incursion.

Frederiksen said she could not promise “no drones will cross the border” but added Copenhagen had “raised the alert level” and was stepping up its drone-repelling defenses.