BRUSSELS (Reuters) - Belgium will keep the highest threat level for Brussels on Monday, with the metro as well as schools remaining closed because of a "serious and imminent" threat of coordinated, multiple attacks, the country's prime minister said.

For the rest of the country, a threat level of three on a four tier scale would remain in place, prime minister Charles Michel said.

"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," Michel told a press conference in Brussels.

Possible targets were malls, shops and public transport, Michel said, adding the government would boost police and army presence in the capital.

Belgium has been at the heart of investigations into the Paris attacks after links to Brussels, and the poor district of Molenbeek in particular, emerged.

Fugitive suspected militant Salah Abdeslam, 26, slipped back home to Brussels from Paris shortly after the attacks, in which his elder brother Brahim blew himself up at a cafe.

Fears of the risks he still poses prompted the cancellation last week of an international friendly soccer match in Brussels against Spain.

(Reporting by Philip Blenkinsop and Robert-Jan Bartunek; editing by Julia Fioretti)