Three European Parliament buildings were evacuated due to a bomb threat. Nearby Montoyer Street was closed for all traffic.
The evacuation was mostly a precaution, police say, after a suspicious-looking man had been spotted in the area.
One suspect was apprehended, a man wearing a military uniform and acting suspiciously.
The suspect was also carrying car keys, which fitted a nearby car.
This vehicle was searched using a sniffer dog. The bomb disposal unit DOVO was also called to the scene, but in the end it nothing was found.
The American embassy also had a bomb scare.
According to Francophone sources, a man had parked a car in front of the building in order to flee the area immediately after. The area was closed due to safety reasons by the police.
One hour later, the ban to enter the area was lifted again.