Talks on European ‘drone wall’ as Denmark says ‘hybrid attack’ behind airport incursions

European ministers are to meet for urgent talks on building a “drone wall” to defend against incoming incursions from the skies after Denmark said it had been the victim of a “hybrid attack” on four airports in the second such incident in days.

Ministers from 10 European countries, including Ukraine, will hold talks on Friday to discuss plans for what the European Commission president, Ursula von der Leyen, has described as “the bedrock of credible defence”.

The drone sightings in Denmark began shortly before 10pm on Wednesday and ended just before 1am on Thursday. Flights were halted for several hours at Aalborg airport, which also serves as a military base, and Billund, Denmark’s second biggest airport, closed its airspace for nearly an hour.

Airports in Esbjerg, Sønderborg and Skrydstrup – home to some of the Danish military’s fighter jets -were also affected. Copenhagen airport was forced to close on Monday night as a result of the presence of three drones.

Von der Leyen backed plans earlier this month for drone defences, but details have until now been scant. The commission’s spokesperson on defence, Thomas Regnier, said the meeting would be a chance to discuss capabilities while stressing the challenges.

“One thing that we will have to do is detect these incoming drones. This is not super-easy to do. We’re not talking about big fighter jets and planes coming in. No, we are talking about the latest technology developments. These drones have to be detected, and then, second track [will be to decide] what will we do to fight back against these drones,” he said.

Ministers from Denmark, the three Baltic states, Finland, Poland, Romania and Bulgaria are expected to take part in the meeting. The commission has indicated that a drone wall could be funded by the EU’s €150bn (£131bn) Security Action for Europe loans scheme.

Denmark’s defence minister, Troels Lund Poulsen, told a press conference: “There can be no doubt that everything points to this being the work of a professional actor when we are talking about such a systematic operation in so many locations at virtually the same time. This is what I would define as a hybrid attack using different types of drones.

“This is an arms race against time because technology is constantly evolving.”

The Danish prime minister, Mette Frederiksen, said she had spoken to the Nato secretary general, Mark Rutte, about “the serious situation related to drones over Danish airports”.

Among the theories being investigated in relation to the Copenhagen airport incursion is that the drones were launched from the sea. Police said they were looking at a number of vessels of interest. They did not name any, but online ship trackers show that two Russian ships were in the area at the time. The Danish broadcaster TV2 suggested they could have been appropriately positioned for Wednesday’s incidents.

The Russian embassy in Copenhagen rejected any speculation that Moscow had been involved in the incidents as absurd, and described the disruptions as a “staged provocation” to escalate tensions.

Police in Denmark and Sweden said they were investigating a number of reports of drone sightings, including over Danish oilfields and Stockholm. Danish ministers have said Copenhagen is “not ruling out anything in terms of who is behind this”.

Poulsen said Denmark was considering activating Nato’s article 4 for the first time in Danish history, but a decision had not yet been made. “In addition to article 4, there are other things that can be done through Nato,” he said.

Rutte said Nato was taking the situation “very seriously”. “Nato allies and Denmark are working together on how we can ensure the safety and security of our critical infrastructure,” he said.

The government has faced criticism in recent days for not shooting down the drones. Poulsen said the Danish armed forces had “a number of capabilities”, but that they would like to have more.

The justice minister, Peter Hummelgaard, said the country would seek additional ways to neutralise drones, including proposing legislation to allow infrastructure owners to shoot them down.

The drone flights follow similar incursions in Poland and Romania and the violation of Estonian airspace by Russian fighter jets, incidents that have raised tensions in light of Russia’s continuing invasion of Ukraine.

“The threat from hybrid attacks is here to stay,” said Hummelgaard, describing recent events as “deeply worrying incidents across Europe”.

Poulsen said the drones may have been launched in the “immediate area” of Denmark. “I can’t describe where they came from, but not over a long distance. It’s happening here locally,” he said.

Military drone experts said it would technically be possible to have flown the drones from far away avoiding detection – especially if using 5G – using a method known as groundhugging, or they could have been launched from nearby, controlled by a pilot who could be anywhere in the world.

The director of the Danish military drone producer Hecto Drone, Andreas Kold Siggaard, said jamming the signal would not make a difference in stopping an advanced drone. “Jamming is not an option. There is not much you can do other than shoot them down or using some kind of kinetic impact, drone-on-drone combat basically,” he said.

Danish police said the sightings on Wednesday night followed a similar pattern to the ones that shut down Copenhagen airport on Monday.

According to North Jutland police, “more than one drone” was seen near Aalborg airport flying with lights on. The first was seen at about 9.44pm local time and drones were still in the airspace after midnight.

Frederiksen has described the drone incursion that shut Copenhagen airport for several hours on Monday as the “most serious attack on Danish critical infrastructure to date”.