Soldiers patrolled the streets of Brussels on the third day of a security lockdown on Monday and the tenth day of a manhunt for the suspected mastermind of the Nov. 13 attacks in Paris.
Belgian national Salah Abdeslam has not been found despite 19 raids and 16 arrests overnight and authorities are still warning of possible imminent attacks like those in the French capital, in which 130 people were killed.
Brussels' metro, museums and schools, many shops and cinemas will stay shut on Monday in the usually bustling European Union capital where many staff will stay to work from home.
An armoured military vehicle was parked under an illuminated Christmas tree in front of the city's landmark Grand Place.
Prime Minister Charles Michel said the city of 1.2 million will remain on the fourth and highest level of security threat, meaning the threat of an attack was "serious and imminent".
"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," he told a news conference.
Belgian Interior Minister Jan Jambon told RTL radio however Belgium's capital was not giving up completely.
"Apart from the closed metro and schools, life goes on in Brussels, the public sector is open for business today, many companies are open," Jambon said on Monday morning.
Authorities were due to review the situation again on Monday afternoon.
Belgium has been at the heart of investigations into the Paris attacks after law enforcement bodies said two of the suicide bombers had lived there. Abdeslam, the main suspect, had returned home to Brussels from Paris shortly after the attacks.
Among those who decided to go out on Monday was Zineb Toubarhi, a business engineering student in Brussels, who was waiting to catch a bus on a frosty morning.
"I am going to my friends' place to look after their children today. They must go to work and the schools are closed. I've had classes cancelled at the university so I will help them," she said.
"It feels strange to see armed soldiers in the streets but this is for our security. So, I don't know why, but I am not afraid."