The discovery of a small drone carrying explosives at Leipzig airport, a leading shipping and military hub, set off alarm and caused flight diversions on Wednesday morning. German police deployed a bomb disposal robot to defuse and destroy the explosive device.

Investigators said “a drone carrying an unknown explosive device was spotted by an airport employee in the security area of the cargo operations zone near the south runway” of Leipzig airport, a facility classified as “critical infrastructure”.

“A suspected second unidentified flying object collided with a cargo aircraft after it had taken off again following the previous closure of the runway. Minor damage was detected on the aircraft after it landed in Hanover,” the investigators said.

A Nato official said: “We are aware of the incident, which the German authorities continue to investigate.”