Danish authorities are investigating a major drone incursion over Copenhagen Airport that forced its closure for several hours, and have not ruled out the possibility of Russian involvement.

Prime Minister Mette Frederiksen described the event as the “most serious attack to date” on Denmark’s critical infrastructure.

Intelligence and police officials are treating the incident as a potential hybrid attack by a capable state actor.

On the evening of September twenty-second, two to three large, unidentified drones approached Copenhagen Airport from multiple directions, intermittently flickering their lights.

The airport, the busiest in Scandinavia, was shut down for nearly four hours as authorities assessed the threat.

Operations resumed only after the drones had vanished.

Norway also experienced a similar shutdown at its main airport, with both countries investigating the possibility that the incidents are linked.

Frederiksen and Denmark’s intelligence chief, Flemming Drejer, said the pattern of recent airspace violations, cyberattacks targeting airports across Europe, and drone incursions suggests these actions may form part of a broader strategy.

While no definitive proof has yet been presented that links Russia to this event, the government considers it a hypothesis under investigation.

Kremlin officials have dismissed allegations of involvement, calling them unfounded.

Investigations are underway jointly among Denmark’s police, intelligence services, and international partners.

Officials are exploring possible launch points, including from maritime vessels, as well as technical characteristics of the drones and their operators.

The incident has heightened concern among European Union and North Atlantic Treaty Organization members over hybrid threats targeting critical infrastructure, especially in and around air traffic hubs.

Discussions are ongoing about bolstering deterrence, including whether an EU-led “drone wall” should be deployed along eastern border regions.