Belgian police arrested 16 people after mounting raids across Brussels and in the south of the country late Sunday, while the prime minister announced another day of lockdown in the capital for fear a new, Paris-style mass attack may be imminent.

At the same time, police said the manhunt continued for a suspect missing since the Nov. 13 attacks in Paris.

Federal prosecutor Eric Van Der Sypt said that "no firearms or explosives were discovered" in the 22 raids — 19 in Brussels and the three in the city of Charleroi in the country's south.

"The investigation continues," he said. One of those detained was injured when a car he was in tried to

ram police during an attempted getaway.

Shortly before midnight, the country's public broadcaster said the law-enforcement operations had concluded.

Armed police mounted searches in several parts of the capital Sunday evening and cordoned off areas close to the city's main tourist attraction, the Grand Place around the town hall.

In another development, the Canadian government said its embassy in Brussels will be closed "until further notice" and will only be providing emergency consular services.

Canadians in Belgium have been advised to "exercise a high degree of caution due to the current elevated threat of terrorism."

<a href="https://twitter.com/hashtag/Belgium?src=hash">#Belgium</a>: our embassy in <a href="https://twitter.com/hashtag/Brussels?src=hash">#Brussels</a> is closed until further notice and will only provide emergency consular services <a href="https://t.co/NFsFHHU5yF">https://t.co/NFsFHHU5yF</a> —@TravelGoC

Meanwhile, people in Brussels braced for widespread disruptions Monday with schools and the subway system closed — and with armed police and military personnel guarding landmarks including railway stations.

Government officials said they were working to return things to normal "as soon as possible" and said they will reassess the situation Monday afternoon.

This undated photo provided by French police shows 26-year-old Salah Abdeslam, a Belgian-born French national who is wanted in connection with the attacks in Paris. (Police Nationale/Associated Press)

The city's streets remained relatively empty and subways were closed for a second day under the alert.

Belgium's national crisis centre, a body that advises the government on security measures, raised the threat alert in the Brussels region on Saturday to Level 4, which indicates a "serious and immediate threat" of an attack.

The rest of the country was on Level 3, meaning a possible and probable threat.

"Nobody is pleased with such a situation. Neither are we. But we have to take our responsibility," said Belgian Prime Minister Charles Michel.

"The weekend is one thing, but moving into the work week is quite another," Georg Von Harrach, a freelance journalist in Brussels, told CBC News.

"Around 350,000 people commute into Brussels during the working week. It's going to cause huge disruptions to them – and also a lot of questions for families that have to look after their children," he said.

Along with subways, underground trams remained closed, along with malls and commercial centres, and officials recommended that sports competitions and all activities in public buildings should be cancelled.

'We fear an attack'

"We fear an attack like in Paris, with several individuals, perhaps in several places," Michel said.

The decision to raise the alert was taken "based on quite precise information about the risk of an attack like the one that happened in Paris," he said.

The move came as the manhunt continued for suspected militant Salah Abdeslam, 26, who slipped back home to Brussels from Paris shortly after the carnage in neighbouring France just over a week ago.

Two of the Paris suicide bombers, Salah's brother Brahim Abdeslam and Bilal Hadfi, had been living in Belgium.

'Threat is wider'

Belgian Interior Minister Jan Jambon on Sunday said "several suspects" tied to the Paris attacks could be at large in the country. Jambon told Flemish broadcaster VRT this is why Belgium has put so many security resources in place in the past few days.

Belgian soldiers patrol at Zaventem international airport near Brussels on Saturday as the city was on high alert of an impending attack. (Francois Lenoir/Reuters)

Jambon added that the threat facing Brussels wouldn't necessarily disappear if Abdeslam was found, because "unfortunately, the threat is wider than this [one] figure."

In light of events in France and Belgium, the 15 members of the UN Security Council quickly and unanimously passed a resolution on the Islamic State of Iraq and Syria (ISIS) on Friday.

France has intensified its aerial bombing in Syria since ISIS militants attacked a concert hall, cafés, restaurants and a stadium in Paris, killing 130 people and wounding hundreds.

Defence Minister Jean-Yves Le Drian told French media on Sunday that ISIS must be destroyed at all costs.

On Sunday, French police issued a photo of one of the suspects involved in the attack outside the French national stadium just north of Paris and appealed for help in identifying him.

[<a href="https://twitter.com/hashtag/Appel%C3%A0T%C3%A9moins?src=hash">#AppelàTémoins</a>] La <a href="https://twitter.com/hashtag/PJ?src=hash">#PJ</a> cherche à identifier le 3ème auteur d'un des attentats du 13/11 <a href="https://twitter.com/hashtag/StadeDeFrance?src=hash">#StadeDeFrance</a> <a href="https://twitter.com/hashtag/ParisAttacks?src=hash">#ParisAttacks</a> <a href="https://t.co/TZxieSUlyY">pic.twitter.com/TZxieSUlyY</a> —@PNationale