Officials believe around 500 Belgians may have gone as foreign fighters to Syria, joining up with jihadis from the Islamic State group which claimed the November attacks on the French capital.
And with Libya in turmoil since the 2011 revolution, there are growing fears it could provide fertile ground for IS recruitment in a region much closer to Europe.
A spokesman for the federal prosecutor's office said police arrested the four in Jumet, near the airport in the southern city of Charleroi, because they were "possibly planning to go to Syria or Libya."
The arrests were not linked to the ongoing investigation into Paris attacks, he said.
Belgian police have arrested 11 people in connection with the November 13 attacks in Paris which left 130 people dead and hundreds wounded since it emerged that the violence was largely organised and coordinated from Belgium.
Earlier this month, the authorities identified three safe houses used by key suspects -- in Brussels, in Charleroi, an hour's drive south of the capital, and in Auvelais, a village near the French border.
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
