Belgian authorities have raised security in the port of Antwerp after a suspicious car ran a red light before being stopped at the docks.
The bomb squad was brought in and the authorities raised security in the centre of town, in places where people normally gather.
Antwerp police chief Serge Muyters said the driver of the car was detained once it was stopped. No further information could be given.
Prime minister Charles Michel said: "We remain vigilant. Our security services have done excellent work."
The events happened on the day after the nation held remembrance services for the Brussels attacks, which killed 32 people on March 22 2016.