Police were deployed to the Porte de Hal district following reports of the explosive cylinders.
The Belgian news network, RTL Info, reported that an “important” police deployment had been ordered in response to the situation and that soldiers had also been called to assist.
According to reports sent into RTL: “The whole area in front of the castle of the Porte de Hal is closed.
“Traffic is also at a standstill and public transport has been stopped.”
Marie Verbeke, a spokesperson for the Brussels-Midi police area, said police wanted to control a “suspect” vehicle in default of insurance and they found three gas cylinders inside.