Chaos has erupted in two major European airports after numerous drone sightings plunged air traffic control into mayhem.
Denmark's Copenhagen Airport saw all its flights ground to a halt, while all traffic at Norway's Oslo Airport was forced to move on to one runway after the unidentified drones were spotted.
Norwegian authorities have confirmed that two people were arrested at the airport shortly after the incident.
In a statement earlier, Danish authorities said: "(The airport) is currently closed for take-off and landing, as two to three large drones have been seen flying in the area.
PICTURED: Danish police at Copenhagen Airport. Danish authorities revealed that 'two to three large drones have been seen flying in the area'
|REUTERS
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"The time horizon is currently unknown."
The flying objects were detected flying around the airspace above Denmark's largest airport at around 8.30pm on Monday.
Copenhagen Airport told local media that an investigation into the drone sightings was underway.
A spokesman said: “The police are investigating the matter, until they have more information, the airspace is closed.
Copenhagen Airport told local media that investigations into the drone sightings were underway (file photo)
|GETTY
“We hope that passengers can soon depart safely and land safely.”
At 11.30pm, Copenhagen Airport re-opened - three hours after the first sightings of the drones.
However, the Danish transport hub warned passengers that "there will be delays and cancelled departures".
Norwegian authorities confirmed on Monday evening that police had received reports of a drone breaching Oslo Airport's exclusion zone at 8.30pm - the exact same time as the sightings in Copenhagen.
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Norwegian Police received reports of a drone breaching Oslo Airport's exclusion zone at 8.30pm on Monday (file photo)
|GETTY
Eastern Police District operations manager Gisle Sveen told TV2: "We acted on that report by having the patrol we have stationed at the airport attempt to locate a drone. They did, and it has now been seized.
"We have not yet found a drone pilot, but are working on this."
Ms Sveen saidthat Norwegian police were aware of the similar incident at Copenhagen Airport, but noted that there is "no information at this time that indicates that this has any connection to what is happening there."
She added: "We are of course vigilant in relation to the drone observation, and still hope to find the drone pilot."
Shortly after 11pm, a second drone was flying in the exclusion zone at Oslo Airport.
A spokeswoman for the transport hub told local media: "The airspace over Oslo Airport is closed due to a new drone sighting."
Flights heading in to Norway's capital city have been diverted to other airports within the country.
Last year, Oslo Airport reported more than 1,400 incidents of unauthorised drones breaching its exclusion zone.
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