By Michael Rios, Ivana Kottasová

(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 were allowed 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, Jespersen said.

“It’s an actor who has the capabilities, the will and the tools to show off in this way,” he said, adding that no suspects have yet been identified.

When asked about the incident Tuesday, Denmark’s Prime Minister Mette Frederiksen said she “cannot reject in any way that it could be Russia” that was behind it.

Ursula von der Leyen, the president of the European Commission, said on social media that “while the facts are still being established, it is clear we are witnessing a pattern of persistent contestation at our borders.”

“Our critical infrastructure is at risk,” she said. “And Europe will respond to this threat with strength and determination.”

Kremlin spokesperson Dmitry Peskov called any allegations against Russia “unfounded,” saying that “making unfounded accusations every time leads to the continuation of such statements no longer being taken into account.”

“Our aircraft are guided by international regulations in all their flights and do not violate them in any way,” he said. “Any accusations directed at our military that some borders are allegedly being violated by our aircraft have never once been supported by solid and reliable data or evidence.”

Copenhagen airport, which serves nearly 30 million people each year, reopened around 12:20 a.m. local time (6:20 p.m. ET) but some delays and cancellations were still expected, an airport spokesperson said early Tuesday.

Earlier, arriving flights were redirected to other airports in Denmark, while some were sent to Gothenburg and Malmö in Sweden, according to the airport.

In Norway, the airspace over Oslo Airport was closed for around three hours Tuesday morning due to a separate drone sighting. “This means that incoming flights are now being redirected to the nearest airport,” Communication Manager Monica Iren Fasting told CNN.

Police were investigating the incident, she added.

Oslo Airport reopened around 3:22 a.m. local time (8:22 p.m. ET), Reuters reported, citing a spokesperson for Norwegian airport operator Avinor.

In an earlier incident in Oslo on Monday, Police arrested two foreign nationals for flying drones over a restricted area. Norwegian media reported the drones were flown over the Akershus Fortress, a medieval castle that is sometimes used for government events. There was no immediate indication it was connected to the events at the airport or in Copenhagen.

Europe has been on alert since Russian drones violated both Polish and Romanian airspace earlier this month – prompting NATO allies to pledge to beef up defenses on the bloc’s eastern flank.

This story has been updated.

The-CNN-Wire
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