Brussels will again see its metro and many shops closed, as well as schools, while offices in a city that is also home to the European Union and NATO are likely to have few staff after the prime minister warned of imminent Paris-style attacks.
Salah Abdeslam, the 26-year-old suspect from Brussels who has been on the run since he left Paris hours after his elder brother blew himself up at a cafe there, continues to elude a Europe-wide manhunt. A third brother, who was not involved, said Abdeslam may have thought better of going through with the killing. Belgian police fear he returned home to launch new attacks.
"What we fear is an attack similar to the one in Paris, with several individuals who could possibly launch several attacks at the same time in multiple locations," Prime Minister Charles Michel told a news conference early on November 22 evening.
Shortly afterwards, armed police backed by armored vehicles and helicopters stationed overhead began a series of raids in which 19 premises in Brussels and three in the industrial city of Charleroi, 50 km (35 miles) to the south, were searched.
Prosecutor Eric van der Sypt told a news conference early on November 23 that no weapons or explosives were found and that a judge would review the detentions of the 16 arrested. In one incident, police fired on a car that was later found in Brussels, but it was not clear, van der Sypt said, if it was linked to the case.
"Abdeslam Salah was not found during the raids," he added.
Several Belgian media carried unsourced reports saying Abdeslam had been spotted in a car near Liege heading towards the German border. There have been numerous reported sightings in recent days, but Abdeslam, a petty criminal who ran a bar in Brussels' Molenbeek immigrant quarter, has eluded police.
Three people have so far been charged in Belgium, where French authorities say the Paris attacks were organized among Brussels' substantial network of Islamic State followers, some of whom have fought in Syria.
Two admit they drove Abdeslam back to Brussels from Paris but deny taking part in any violence.