Brussels to stay at highest security alert, hunts 'several' suspects

Brussels will remain at the highest possible alert level on Monday with schools and metros closed over a "serious and imminent" security threat in the wake of the Paris attacks, the Belgian prime minister said.

Armed police and troops have been patrolling the near deserted streets of the tense capital all weekend after the government raised the terror alert to the highest level of four in a city of one million that is also home to the NATO and European Union headquarters.

Following a meeting of the national security council on Sunday, Premier Charles Michel said the shutdown of the metro system would be extended and all schools would be closed over concerns that jihadists were planning a repeat of the Paris gun and suicide bombing attacks that claimed 130 lives on November 13.

"What we fear are similar attacks, with several individuals in several places."

Michel said the rest of the country would remain on security alert level three, meaning an attack is considered possible and the threat credible. "The threat is considered serious and imminent," he told reporters.

He said he was aware the situation was "very difficult for everyone".

"We are doing everything possible to return to normal life," he said, adding that officials would review the situation again on Monday.

Caption: Belgian soldiers patrol in the departure hall of Zaventem international airport near Brussels (VOA)