Sweden is sending radar and military anti-drone systems to Denmark ahead of European summits in Copenhagen this week, after drone incursions that forced Denmark to shut several airports.
Denmark is due to host EU leaders on Wednesday, followed by a summit on Thursday of the wider, 47-member European Political Community, and has already said it has increased security around the events after the drone sightings.
Denmark will ban all civilian drone flights across the country over the coming days to ensure security .
Ulf Kristersson, the Swedish Prime Minister, said on Monday Russia was likely behind mysterious drone flights over several airports.
Drone sightings across Denmark since September 22 have prompted the closure of several airports, with the Danish government hinting at possible Russian involvement, though Moscow denies the charge.
Speaking to Danish TV, Mr Kristersson said "the likelihood of this being about Russia wanting to send a message to countries supporting Ukraine is quite high" but added that "nobody really, really knows".
He added that "we have confirmation" that drones that entered Polish airspace earlier this month were Russian.
"Everything points to [Russia] but then all countries are cautious about singling out a country if they are not sure. In Poland, we know that's what it was," he said.
Mr Kristersson said in a post on social media X that Sweden would send "Counter-UAS" – unmanned aircraft systems – and that his country had also shipped "a handful" of radar systems to Denmark.
Drones were observed over Danish military sites on Saturday night for the second consecutive day, Denmark's army said.
Intelligence services said last week Denmark was facing a “high threat of sabotage”, after a “skilled” pilot flew two or three large unidentified drones over Copenhagen Airport, shutting the airspace for hours.
Copenhagen is to host the EU summit on Wednesday and Thursday. Transport Minister Thomas Danielsen said: “Denmark will host EU leaders in the coming week, where we will have extra focus on security.
"Therefore, from Monday to Friday, we will close the Danish airspace to all civilian drone flights. In this way, we remove the risk that enemy drones can be confused with legal drones and vice versa.
A breach of the ban can result in a fine or imprisonment for up to two years, the ministry said.
Justice Minister Peter Hummelgaard said the purpose of the ban was to simplify the work of police and other authorities. “The police are on heightened alert, and our authorities must use their forces where necessary to take care of Danes and our guests.”
He said the ban would mean police would not have to “spend their efforts on civilian drones” that do not pose a problem to security and police.
Danish police said on Saturday they had received more than 500 reports of drone flights from the public, most of which were dismissed as being of no interest.
In neighbouring Norway, airport operator Avinor said on Sunday that drone “activity” was observed at Bronnoysund Airport, one of four airports in northern Norway where air and land restrictions for drones had been extended to 10km from Saturday until Monday as “a precautionary measure”.
“This affected one incoming flight, which was instructed to delay its landing and has now diverted to an alternate airport,” Avinor said.
Avinor provided no details about the number of drones observed or where they may have come from.
Nato 'enhances vigilance'
Norway is already investigating “possible sightings of drones” on Saturday near its largest military base, Orland, where its F-35 fighter jets are parked.
And Germany said on Saturday it wants to authorise its military to shoot down drones after a “swarm” was spotted over the northern state of Schleswig-Holstein, which borders Denmark.
Nato said it had “enhanced vigilance” in the Baltic following the intrusions.
The reinforced measures “include multiple intelligence, surveillance and reconnaissance platforms and at least one air-defence frigate” in the region to the west of Russia, alliance spokesman Martin O'Donnell said.
The string of drone sightings in the past week comes on the heels of drone incursions in Polish and Romanian territory and the violation of Estonian airspace by Russian fighter jets, which raised tension in light of Russia's continuing invasion of Ukraine.
Danish investigators have so far failed to identify those responsible for the drone flights over Denmark. But Prime Minister Mette Frederiksen said this week that “there is one main country that poses a threat to Europe's security, and it is Russia”.
Moscow said on Thursday it “firmly rejects” any suggestion that it was involved in the Danish incidents.
Defence ministers from about 10 EU countries agreed Friday to make a so-called “drone wall” a priority for the bloc.
