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.
Belgian PM Charles Michel said he would maintain the highest security threat level in Brussels,
warning of an imminent threat.
But authorities plan to reopen schools and the metro on Wednesday.
The co-ordinated assaults in Paris by the extremist group ISIS left 130 people dead.
A statement from the federal prosecutor’s office said the man had been charged with “participating in activities of a terrorist group and with [a] terrorist
Of the five people arrested on Monday morning, two have been released while “further enquiries” are under way regarding the others, the prosecutor said.
Mohammed Amri, 27, and Hamza Attou, 20, have already been charged with aiding Paris attacks
suspect Salah Abdeslam, who remains at large. A third, unnamed suspect has also been charged.
In a separate development, French police said what appears to be an explosives belt was found in a
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 in place, Mr Michel stressed “we must all progressively get back to a normal life”.
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
French jets bombed IS targets in Iraq, the defence ministry said.
President Francois Hollande has vowed to intensify strikes against IS in Syria and Iraq in the wake of
French media have reported that nine militants carried out the attacks on 13 November, and seven died.