Belgian Justice Minister Koen Geens said "a number of'' arrests have been made in Brussels relating to the Paris attacks.
Belgian TV says five people were detained in the suburb of Molenbeek.
The arrests come after a car with Belgian registration plates was seen close to one of the attacks - the Bataclan concert hall.
As the investigation continues, French police are trying to establish the attackers' identities.
One of those involved in the Bataclan concert hall attack is reported to have been a French citizen with a history of involvement in radical Islam.
A Syrian passport was found next to the body of one of three suicide bombers who struck near the Stade de France stadium during the game.
A Greek minister says the passport belonged to a Syrian refugee who passed through the island of Leros. An Egyptian passport has also been linked to the attacks.