Brussels police on Saturday faced off against about 100 "Yellow Vests" protesters on Rue de la Loi, denying them access to the European Quarter, where the demonstrators intended to hold an unauthorised rally.
"Around 100 people have already been detained," Brussels police spokeswoman Ilse Van De Keere said.
Law enforcement officers had already detained about 70 people earlier on suspicion that they intended to join protesters in various areas of the capital, Ilse Van De Keere told reporters.
Many trains this Saturday did not stop at Brussels Central Station; Parc metro station is closed in the centre of the city near government offices. The rest of the city's subway system is still functioning normally.
Ilse Van de Keere told RTBF that local and federal police, as well as firefighters and employees of Brussels' transport services, are cooperating in order to ensure order.