Air traffic over Belgium has been temporarily suspended after flight data processing system failed, according to the country’s air traffic controller Belgocontrol.

The flight data processing system of the Belgian traffic controller has at some point failed to trace the aircraft location over Belgium’s territory, prompting the Belgocontrol to take an “ultimate safety measure” and “clear the sky,” the local De Morgen daily reported.

The air controller was also unable to determine the destination, altitude and speed of the planes that were in the air, it added.

The Belgocontrol spokesperson, Dominique Dehaene, told the media that a “technical problem” as caused the system disruption, adding that there was “no threat of any kind.”

The Belgian airspace was closed shortly after 16:00 (local time) (14:00 GMT). The measure is expected to remain in effect at least until 17:00 GMT, according to Reuters.

All flights en route to Belgian airports were rerouted while those scheduled to depart from Belgium were kept on the ground.