Denmark’s Aalborg airport in the country’s north has been closed after unauthorised drones were seen in its airspace, according to local authorities.
The incident comes after the country’s Copenhagen airport was forced to close earlier this week due to a drone incursion, which the prime minister described as “the most severe attack on Danish infrastructure so far”.
Police confirmed that drones have been observed near the airport and the airspace has been closed as they investigate the incident.
At least three flights have been diverted and officials said it was unclear the purpose of the drones or who is controlling them.
Danish national police said that the Danish Armed Forces were also affected as Aalborg airport is also used as a military base.
The North Jutland Police released a statement saying they were monitoring the situation closely but could not elaborate on how many drones were involved.
“We cannot yet comment on the purpose of the drones flying in the area, nor can we say anything about who the actor behind it is,” chief inspector Jesper Bøjgaard Madsen said.
“If we get the opportunity, we will take down the drones,” he added.
Police said they did not believe there is any danger to passengers at the airport or residents, but asked the public to keep their distance from the area.
They said the devices could be seen from the ground and added that they couldn’t rule out the activity being a prank.
Of the three flights affected, two were sent back to Copenhagen, and another back to the town of Karup.
The agency that oversees European air traffic control said arrivals and departures at the airport would be stopped until 06:00 local time (04:00 GMT) on Thursday.
On Monday, Kastrup airport in Copenhagen was forced to shut for several hours following the sighting of a number of drones.
“It says something about the times we live in and what we as a society must be prepared to deal with,” Prime Minister Mette Frederiksen told reporters.
Russian involvement could not be ruled out, he added – although Kremlin spokesman Dmitry Peskov called the allegations “unfounded”.
Europe has been on high alert after several Nato member states reported Russian drone incursions in their airspaces.
Last week, Estonia and Poland requested a consultation with other Nato members, after Russia violated its airspace in separate incidents.
Romania, another Nato member, also said Russian drones breached its airspace.
Russia denied violating Estonia’s airspace, while it insisted the Polish incursion was not deliberate. It did not comment on the Romania incident.
After meeting on Tuesday, Nato issued a statement condemning Russia’s actions and warned that it would use “all necessary military and non-military tools” to defend itself.
“Russia bears full responsibility for these actions, which are escalatory, risk miscalculation and endanger lives. They must stop,” it said.
Nato’s secretary general Mark Rutte said: “We are a defensive alliance, yes, but we are not naive, so we see what is happening.”
After his speech to the UN, Donald Trump suggested that Nato nations should shoot down Russian planes breaching their airspace.