Denmark’s minister of defence,Troels Lund Poulsen,has requested help from his Nordic colleagues and NATO following the incidents,according to Danish TV2.

He asked for assistance with additional technology and capacity.

Drones were also spotted hovering near the Oslo airport,but it is not known whether the incidents were connected.

Karlskrona,where the latest drones were seen,is around 150 miles east of Copenhagen Airport.

The aviation industry is on high alert across the US and Europe after a cyber attack disrupted operations across major airports,including Heathrow,Brussels and Berlin.

Airline staff were forced to manually input passenger and baggage details after a cyber incident affecting Collins Aerospace which provides ground services across many airports.

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