Brussels: Belgian authorities have detained a suspect who was driving with gas canisters in the back of his car, setting off a security alert in the centre of Brussels.

The prosecutor's office said a busy part of the capital was closed off and a subway station closed during the evening rush hour.

Prosecutor's spokeswoman Ine Van Wymersch said authorities did not want to take any chances and acted quickly "since the driver was known by judicial authorities and it was unclear why the gas canisters were there."

"We are taking the case seriously," Van Wymersch added.