According to Politiken, this is not the first time drone activity has been observed in the North Sea area.
The National Police has not commented on the situation.
The drones were last seen on September 28 near the Halfdan B oil and gas field.
According to the publication, such flights can be carried out "only by advanced drones", and not by "regular commercial UAVs."
Such drones can be launched "from a ship or a submarine".