Brussels alert status "remains at the highest level", Belgium's Prime Minister said on Sunday.
Prime Minister Charles Michel said the alert status for Brussels would remain at level four, and the rest of Belgium would remain at level three, as the country still "fear an attack like in Paris".
He told a press conference:
What we fear is an attack similar to the one in Paris, with several individuals who could also possibly launch several attacks at the same time in multiple locations.
Warning that Belgium believed possible targets could be commercial centres, shops and public transport, Michel said the army and police presence across the country would be strengthened.
It was also confirmed that Brussel's metro system and schools would remain shut on Monday in light of the heightened security.
Andy Murray says Great Britain's tennis players feel "very comfortable" in Belgium as they prepare to play in Friday's Davis Cup final
Walking round Brussels today is a bit like walking round a city on Christmas Day - it's a touch surreal.
Former British number one Tim Henman has cancelled his plans to attend the Davis Cup final with his family amid security fears in Belgium.