Belgian police have charged a fourth suspect with terrorism offences related to the deadly attacks on Paris, the federal prosecutor has said.
The unnamed man was one of 16 people arrested in raids on Sunday. The rest have been released without charge.
A statement from the federal prosecutor's office said the man had been charged with "participating in activities of a terrorist group and with terrorist attack".
Two of five people detained on Monday were also released while the other three had their custody prolonged.
France and Belgium have launched a manhunt following the attacks that killed 130 people, with a focus on Brussels barkeeper Salah Abdeslam, 26, who returned to the city from Paris hours after the attacks and is still at large. Islamic State (IS) claimed responsiblity for the co-ordinated assaults in Paris on 13 November.
Salah Abdeslam's mobile phone was detected after the attacks in the 18th district in the north of Paris, near an abandoned car that he had rented, and then later in Chatillon in the south, a source close to the investigation told Reuters.
Mohammed Amri, 27, and Hamza Attou, 20, have already been charged with aiding Salah Abdeslam. A third, unnamed suspect has also been charged.
In a separate development, French police said an object that appeared to be an explosives belt was found in a bin in the Paris suburb of Montrouge on Monday. The item is being examined.
Mobile phone data suggest that Salah Abdeslam - whose brother died in the attacks - was in that area late on the night of the attack.
Brussels remains on high security alert
Universities, schools, large stores, shopping centres and the metro system were closed in Brussels on Monday as the highest security alert remained in place for a third day.
Armed police patrolled the normally bustling streets of the capital.
Announcing that the state of alert would remain at level four for another week, Mr Michel stressed "we must all progressively get back to a normal life".
Authorities planned to reopen schools and the metro on Wednesday.
The rest of Belgium remains on alert level three, meaning an attack is seen as possible and credible.
France has stepped up security in schools, imposing a series of measures including compulsory safety drills and banning parking outside school premises.
Also on Monday, France carried out its first strikes against IS from its Charles de Gaulle aircraft carrier, newly deployed in the eastern Mediterranean.
French jets bombed IS targets in Iraq and Syria, including Raqqa, IS's key Syrian stronghold, the defence ministry said.
-BBC / Reuters