BRUSSELS (AP) — Belgian authorities tightened security Thursday in the port city of Antwerp after a Frenchman drove his car at high speed through a busy shopping area, forcing pedestrians to jump out of the way. At first sight, the incident appeared to have the hallmarks of several extremist attacks in Europe — a vehicle in a busy area bent on mowing down pedestrians. The high-speed event happened a day after Belgium held anniversary remembrance services for the Brussels airport and subway attacks, which killed 32 people on March 22, 2016.