Police so far have not confirmed to Euronews how many injuries there are from the incident but Belgian media are reporting several.
ADVERTISEMENTA woman was seriously injured and a pregnant woman was pushed over during a knife attack on a metro train in Brussels on Monday afternoon, the prosecutor's office has confirmed.
Police initially confirmed reports of an "incident" involving an individual with a knife.
The attack took place at the Gare de l'Ouest metro station in the Molenbeek area of the city, just before 3pm.
The incident was described as relating to "private life" by the prosecutor's office.
"Following these events, the Brussels Prosecutor's Office ordered the evacuation of the metro train concerned in order to clear the station and allow the FGP LABO to disembark on the metro train," the office said in a statement to Euronews.
It added that it had requested the confiscation of video footage.
A suspect was arrested and is to be questioned by the police.
"No further announcements will be made about the ongoing investigation", the office said.