COPENHAGEN, Sept 26, 2025 (BSS/AFP) - A Danish airport briefly closed again following another suspected drone sighting, police and national media said on Friday, after the prime minister blamed similar incidents this week on "hybrid attacks".

The airspace over Aalborg airport in northern Denmark was shut at around 11:40 pm (2140 GMT) on Thursday because drones had been seen in the area, public broadcaster DR reported, citing an airport official.

The regional police force later said in a statement on X that the closure had occurred due to suspected drone activity, adding that the airspace had reopened at about 12:35 am on Friday.

It was not immediately clear whether authorities had verified the presence of any drones.

The shutdown forced a KLM flight from Amsterdam to turn around, and caused the cancellation of a Scandinavian Airlines flight from the Danish capital Copenhagen, flight tracking sites and airline websites showed.

Danish police said drones were spotted on Wednesday and earlier on Thursday at airports in Aalborg, Esbjerg, Sonderborg and at the Skrydstrup air base before leaving on their own.

That incident had already caused Aalborg airport to shut down for several hours.

Drone sightings also prompted Copenhagen airport to shut down earlier this week.

It followed a similar incident in Norway, drone incursions in Polish and Romanian territory, and the alleged violation of Estonian airspace by Russian fighter jets.

Danish Prime Minister Mette Frederiksen said in a video message on social media on Thursday that the country had been "the victim of hybrid attacks," referring to a form of unconventional warfare.

While investigators have so far failed to identify those responsible, Frederiksen said Russia was the "main country that poses a threat to Europe's security".

Moscow has said it "firmly rejects" any suggestion that it was involved in the Danish incidents, which its embassy in Copenhagen called "a staged provocation".