BRUSSELS (AP) — Belgium's air traffic control center says that no airplanes can land or depart across the country because of a technical glitch in its data system.

Belgocontrol said in a Twitter message that it is executing a "clear sky" until the issue is fixed. It said "there is a problem loading flight data." It did not elaborate.

Dominique Dehaene of Belgocontrol told the VRT network that "it is a very specific problem and it was no longer sure that all information of flights was correct."

Brussels international and Charleroi are the biggest airports in Belgium.