Steven Knap/Ritzau Scanpix/AFP/Getty Images via CNN Newsource

(CNN) — Two of Scandinavia’s busiest airports – Oslo and Copenhagen – were forced to close for several hours due to drone sightings overnight into Tuesday, disrupting the travel plans of tens of thousands of people.

The airspace over Denmark’s Copenhagen Airport was closed for almost four hours on Monday night after two to three large “unidentified” drones were spotted in the area. No flights wereallowed to take off or land.

“We have concluded that this was what we would call a capable operator,” Danish police Chief Superintendent Jens Jespersen told reporters on Tuesday, Reuters reported.

The drones came from several different directions, turning their lights on and off, before eventually disappearing after several hours,

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