Danish police said on Tuesday that drones that shut the country's main airport on Monday appeared to have been flown by "a capable operator", adding that no suspects had been identified.
The airports in Copenhagen and Oslo, the two busiest in the Nordic region, were shut for hours after drones were observed in their airspace late on Monday, leaving tens of thousands of passengers stranded as flights were diverted.
"We have concluded that this was what we would call a capable operator," Danish police Chief Superintendent Jens Jespersen told reporters on Tuesday, referring to the drones observed in Copenhagen.
"It's an actor who has the capabilities, the will and the tools to show off in this way," Jespersen said, adding that it was too early to say if the incidents in Denmark and Norway were linked.
Copenhagen Airport was closed for four hours when two or three large drones were seen flying in its immediate vicinity, officials said, while the Oslo Airport was closed for three hours following two sightings, according to local police.
Jespersen said the drones in Denmark came from several different directions, turning their lights on and off, before eventually disappearing after several hours.
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