Denmark Weighing Up Article 4 Option Following Airport Drone Incursions

Denmark said on Sept. 25 it is considering whether to invoke Article 4 of the NATO treaty following drone incursions into its airspace, which briefly forced two airport shutdowns and affected military bases.

The airports reopened on the morning of Sept. 25 after being closed when unidentified drones flew into their airspace overnight.

It is the second such security incident in the Scandinavian country this week.

Danish Defense Minister Troels Lund Poulsen called it a “hybrid attack” because the drone flights all happened within the same timeframe.

He said during a press conference that it appeared a “professional actor” was behind the “systematic” flights, without providing further details.

Article 4 states that members of the North Atlantic Treaty Organization will consult together whenever, in the opinion of any of them, the territory, political independence, or security of any member is threatened.

The Danish government is holding internal discussions—and discussions with NATO—on whether to invoke Article 4, Poulsen said.

Russian Rebuttal

The Russian Embassy in Denmark rejected all suggestions of Russian involvement and said the incident was “staged.”

In a statement shared on social media, the embassy said: “It is evident that the incidents involving reported disruptions at Danish airports are a staged provocation.

“Undoubtedly, they will be used as a pretext for further escalating tension in the interests of forces seeking by all means to prolong the Ukrainian conflict and extend it to other countries.

“The Russian side firmly rejects the absurd speculations of involvement in the incidents.”

Billund Airport, Denmark’s second largest, was closed for an hour, and Aalborg Airport, used for commercial and military flights, was closed for three hours because of drone incursions late on Sept. 24, Danish police said.

Drones had also been spotted near airports in Esbjerg and Sonderborg, as well as Skrydstrup airbase, home to some of Denmark’s F-16 and F-35 fighter jets.

All five affected airports are located on the Jutland Peninsula in western Denmark.

No Threat to Public

Authorities said they were unable to neutralize the drones but stressed there was no threat to the public.

The goal of the flyovers was to sow fear and division, Danish Minister of Justice Peter Hummelgaard told the press conference, adding that his country will seek additional ways to neutralize drones, including proposing legislation to allow infrastructure owners to shoot them down.

The drones appeared to be flying around the airports with their lights turned on, but authorities decided against attempting to shoot them down, police said.

Danish police said the drones followed a similar pattern to those that had grounded flights at the capital’s Copenhagen airport late on Sept. 22 and early Sept. 23, as well as in Oslo in neighboring Norway.

Danish Prime Minister Mette Frederiksen described the incident at Copenhagen as the most serious “attack” yet on Denmark’s critical infrastructure and linked it to a series of suspected Russian drone incursions and other disruptions across Europe, without giving evidence.

Article 4 Invocation

If Article 4 is invoked by Denmark, it would be the second time this month, following Polish Prime Minister Donald Tusk’s invocation of Article 4 on Sept. 10 after Poland shot down drones in its airspace following what he called a “large-scale provocation” by Russia.

Russia’s defense ministry said its drones had carried out an attack on military facilities in western Ukraine but that it had not planned to hit any targets in Poland.

Article 4 was also invoked in February 2022 when Bulgaria, the Czech Republic, Estonia, Latvia, Lithuania, Poland, Romania, and Slovakia sought consultations following Russia’s invasion of Ukraine.

The Danish flight shutdowns came after a string of disruptions at European airports in recent days.

A cyberattack began on the evening of Sept. 19, causing disruption at major international hubs including Brussels, Berlin Brandenburg, and London Heathrow, Europe’s busiest airport.

A man was arrested in England on Sept. 23 by the UK’s National Crime Agency on suspicion of involvement in the cyberattack that disrupted flights at European airports for several days.

The cyberattack impacted Collins Aerospace, a U.S. company that provides check-in and passenger processing systems.

Reuters, PA Media, and The Associated Press contributed to this story.