Brussels security forces are looking for at least two men, one of who might be carrying a bomb of the same type used in Paris attacks on November 13, Belgian Le Soir reported.
"The advice for the population is to avoid places where a lot of people come together, like shopping centers, concerts, events or public transport stations wherever possible," a spokesman for the government's crisis center said, Reuters reported.
The recommendation came after the government increased its threat scale to “level four” following a meeting of ministers, police and the security services.