Here are the latest updates:

Armed police and soldiers are patrolling the streets, subways are closed and many shops have shut their doors in the Belgian capital Brussels as the government issued a warning over possible Paris-style terror attacks.

At least one suspect from the deadly Paris attacks just over a week ago is at large and was last seen crossing into Belgium.

Belgian prime minister Charles Michel said the decision to raise the threat alert to its highest setting was taken "based on quite precise information about the risk of an attack like the one that happened in Paris ... where several individuals with arms and explosives launch actions, perhaps even in several places at the same time".

At least one Paris attacker, Salah Abdeslam, crossed into Belgium the morning after the attacks. Paris officials say they have no firm information on Abdeslam's whereabouts, including whether he was in the Brussels area.