A 29-year-old man is held in Paris as part of the investigation into the November 13 attacks.
Belgian authorities have detained five people, including two brothers, after two days of raids related to the attacks in Paris in which 130 people were killed.
The federal prosecutor’s office said two people were detained following a house search on Monday in the Laeken district of Brussels.
On Sunday evening, another Brussels house was searched on orders from an investigating judge. Two brothers found there were taken in for questioning, as well as a friend.
Special forces and federal police were involved in the raid which lasted around five hours and took place near the city’s popular tourist area, authorities said.
“They have been taken in for questioning,” Eric Van Der Sypt, spokesman for the federal prosecutor, said of the men, but he gave no further details about them.
However, he confirmed the detained suspects did not include fugitive Salah Abdeslam, who is one of Europe’s most wanted men, over his alleged involvement in the November 13 attacks in the French capital.
The search took place in a building on the outer limits of Molenbeek – an area with a large immigrant population – and less than a kilometre away from Brussels’ central Grand Place square.
The prosecutor’s office said an analysis of phone records led to Sunday’s search. Authorities said they found no weapons or explosives at either residence, and did not identify those detained.
Belgian police are still actively looking for 26-year-old, Brussels-born Abdeslam, suspected of having played a key role in the Paris attacks and understood to have returned to the Belgian capital the day after the bloodshed.
An international arrest warrant is out on Abdeslam, who lived in Molenbeek.
A source close to the Belgian investigation told AFP news agency earlier on Sunday that Abdeslam made it past three police checks when friends drove him from Paris to Brussels in the hours after the coordinated gun and suicide attacks.
Belgium has so far arrested 11 people on suspicion of involvement in the assaults, which have been claimed by the Islamic State of Iraq and the Levant (ISIL) group.