Prime Minister Charles Michel later called an urgent meeting following the incident.
City 2 shopping complex is one of the biggest shopping centers in Belgium and will have been packed with people later today.
A Brussels police spokesman said:
“Following the warning, police and bomb disposal experts attended the scene. A man was arrested.” The emergency is ongoing. Five underground stations have been shut down, and searches are continuing throughout the area.”
City 2 spokeswoman Veronique Pirson said police said “a package had been found right next to City 2.”