The airport in northern Germany said flight operations had been suspended since 6.10am due to a police operation in response to unauthorised individuals close to the landing and takeoff area.

Hamburg airport said some 330 take-offs and landings with 50,000 passengers were scheduled for Thursday, the start of school holidays in the region.

“Flight operations will not be resumed until it has been ensured that all persons have been removed,” it said in a statement.

Dusseldorf airport in western Germany reported delays due to unauthorised individuals on the premises.

The Letzte Generation (Last Generation) protest group, whose members have frequently glued themselves to roads and airport tarmacs in Germany in a wave of civil disobedience, posted videos on Twitter of protesters sitting on the asphalt.