Ostend Airport was evacuated on Wednesday due to a bomb threat but has since reopened.
The airport confirmed the report on Wednesday at midday. According to the City of Ostend, the closure followed the reception of threatening mail to several airports. Security forces are checking the entire airport as a precautionary measure.
No passengers were present in Ostend, but about 50 airport staff had to leave the building.
After a thorough inspection, nothing suspicious was found and the building was declared fit for service. The impact on air traffic remained limited.
Several airports in France were also evacuated on Wednesday. A police source told AFP that six airports were affected: Lille, Lyon (Bron), Nantes, Nice, Toulouse, Beauvais.
A square in Ghent has also been evacuated on Wednesday after the discovery of two suspicious packages.
This article was updated at 16:56.