A suspect shouted out "Allahu Akbar" (God is Greatest) before causing the explosion, a witness said.
Belgium's national crisis said the suspect had been "neutralised" and the situation was under control.
The incident took place around (0030 IST), causing the city's Gare Centrale to be evacuated. The nearby Grand Place, a major tourist destination, was also evacuated.
"I went down the mezzanine level, someone was shouting. Then he cried 'Allahu Akbar', and he blew up a trolley," Nicolas Van Herrewegen, a railway sorting agent, told reporters.
Van Herrewegen added: "It wasn't exactly a big explosion but the impact was pretty big. People were running away."
He described the suspect as well-built and tanned with short hair, wearing a white shirt and jeans.
"I saw that he had something on him because I could see wires emerging, so it may have been a suicide vest," the witness said.
About an hour after the events, the situation was "under control", the federal crisis centre said in a tweet.
"Panic in the Gare Centrale. Shots heard," another witness told the broadcaster.
Firemen were called to the scene after the report of the small explosion, RTBF broadcaster reported.
The incident in Belgium comes a day after a man mowed down Muslims near a mosque in London, and a radical Islamist on a terror watch-list rammed a car laden with weapons and gas into a police vehicle in Paris.
Brussels has been on high alert since Islamic State suicide bombers struck the city's airport and metro in March 2016, killing 32 people and injuring hundreds more.
Soldiers have been deployed at railway stations, government buildings and European Union institutions in Brussels since the aftermath of the Paris attacks when a link to Belgium was first established.
Belgium suffered a further shock last August when a machete-wielding man attacked two policewomen in the industrial town of Charleroi, before being shot dead.
The country's law enforcement agencies and intelligence services came under intense scrutiny after the attacks for apparently missing a series of leads after the Paris attacks that could have led to the Brussels bombers.
Disclaimer: No Business Standard Journalist was involved in creation of this content
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
