Police say the suspect tried to enter a busy shopping street in a car traveling at high speed. Extra security and military personnel have been deployed to the northern Belgian port city.
Authorities boosted security in Antwerp's downtown on Thursday after a car ran a red light and careened towards the city's main pedestrianized street.
Police chief Serge Muyters told reporters people had to "jump aside" to avoid the vehicle before it was intercepted at the port docks.
"A man in camouflage was taken away," Muyters said. The man had reportedly attempted to flee the scene, but was detained. Bomb disposal units were also dispatched to the scene.
There were no reported injuries.
The Belgian federal prosecutor's office identified the suspect as 39-year-old Mohamed R., a French citizen living in France. French authorities, however, said the man was originally from Tunisia. Investigators said they found a rifle, various knives and a gas can containing an unknown liquid inside the car.
The prosecutor's office said "because of these elements, and the events in London yesterday, the case is being taken on by the federal prosecutor's office," which usually deals with extremist attacks. On Wednesday, a knife-wielding man was shot dead by UK police after he had plowed a car into pedestrians on London's Westminster Bridge and stabbed a policeman. Vehicles were also used in deadly attacks in the cities of Nice and Berlin last year.
Suspect not known as extremist
A source affiliated with the French police however told news agency AFP that the suspect's "only previous convictions are minor, such as drunk driving or drug use." According to the source, Mohamed R. "was not on the (French) list of known extremists and according to the initial findings of the investigation had not been flagged up as being radicalized."
French President Francois Hollande compared the incident to the deadly rampage in London that left four people dead. Hollande said the suspect in Antwerp was also "trying to kill people or create a dramatic event."
Belgium on high alert
Belgian Prime Minister Charles Michel said on Twitter the government was "following this situation as it develops" in the Flemish-speaking northern city. "We remain vigilant. Our security services have done excellent work."
Antwerp mayor Bart De Wever described the incident as a "potential attack avoided."
Belgium has been on high alert since March 22 last year when suicide bombers attacked the Brussels airport and subway network, killing 32 people and wounding 320. The country held remembrance services on Wednesday to mark the one year anniversary of those attacks.
nm/kms (Reuters, AFP, AP, dpa)