Denmark has reached out to NATO and the EU after it was forced to close Aalborg airport and placed three other airports on alert on Thursday as unauthorised drones conducted what authorities described as coordinated attacks.
Copenhagen was considering whether to trigger the alliance's Article 4, in what was a hybrid attack involving a "systematic approach" carried out by professionals in flying drones near critical infrastructure, Danish Deputy Prime Minister and Defence Minister Troels Lund Poulsen said at a press conference on Thursday.
