BRUSSELS - A government official says a series of police raids in central Brussels have ended, hours after the government decided to keep its terror alert at the highest possible level.
The situation was tense Sunday night in the wider area around the Grand Place, with police out in force and several raids looking for suspects going on.
At one point, security forces closed off streets and yelled at people to stay away.	The official, who spoke on the condition of anonymity because the investigation was still ongoing, said the results of the raids would be discussed at a press conference to be held shortly.
Some of the attackers in Paris are now known to have traveled to and lived in Brussels, sparking concerns about further attacks there.
Belgian media vowed to stop reporting details of the operation as it is ongoing.
While it appears the Belgian public has largely respected the requests, many had humorous responses on social media.
Belgian Prime Minister Charles Michel said Sunday the government has decided to keep the terror alert at the highest level for a sustained "serious and imminent" threat against the capital.
Michel said that like the weekend, authorities fear a Paris-like attack, "even perhaps at several locations."
The prime minister said the threats appear to be directly against commercial centers, shops and public transportation.
He said schools and the subway system in Brussels would not open as the workweek begins on Monday. Officials have also encouraged the public to remain vigilant and avoid crowds or large public gatherings.
Earlier Sunday, the mayor of one of Brussels' many municipalities told Belgian media that the capital is still facing a grave threat because of the likelihood of there being terrorists connected to the Paris attacks there.
Schaerbeek Mayor Bernard Clerfayt said Sunday: "There are two terrorists in the Brussels region that could commit very dangerous acts."
One of the suspected Paris attackers, Salah Abdeslam, is at large and is known to have crossed into Belgium the morning after the Nov. 13 attacks. The source of the mayor's information about a second suspect wasn't immediately clear and the prime minister's office declined to comment.
Belgian Interior Minister Jan Jambon added on to Clerfayt's statement Sunday by saying "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. Jambon said Sunday that the threat facing Brussels wouldn't necessarily disappear if Abdeslam was found, because "unfortunately, the threat is wider than this (one) figure."
Brussels residents woke up to largely empty streets as the city entered its second day under the highest threat level and the manhunt continued for a suspect missing since the Nov. 13 attacks in France.
Belgium's national Crisis Center on Saturday raised the threat alert in the Brussels region to Level 4, which indicates a "serious and immediate threat."
Belgium government officials held a national security council meeting late Sunday on whether to lower the country's threat alert level and restore normalcy as the work week is set to return on Monday.
Upon entering the security council meeting on Sunday evening, Belgian Vice President Kris Peeters said "tomorrow, we have school. There are the businesses. We have a new situation."	He added that "we have to make decisions to avoid that Brussels will be an empty city."
Subways and underground trams remain closed Sunday and officials recommended that sports competitions and all activities in public buildings should be cancelled and malls and commercial centers closed.
Belgian officials say the measures were recommended due to the extra security they would require. The country's Regional Security Council is set to meet Sunday afternoon to update any new measures needed.
Clerfayt said it was necessary to try to anticipate and prevent any such acts and their consequences.
He said: "As long as this threat is present, we must be very attentive."
France's defense minister said Sunday the French aircraft carrier Charles de Gaulle has been sent to help operations against ISIS militants in Syria will be "operational" from Monday and "ready to act."
France has intensified its aerial bombing in Syria since ISIS militants attacked a concert hall, cafes and restaurants and a stadium in Paris, killing 130 people and wounding hundreds.
Defense Minister Jean-Yves Le Drian told French media on Sunday that ISIS must be destroyed at all costs.
Le Drian said: "We must annihilate Islamic State worldwide," adding: "that's the only possible direction." He said any country "who wants to participate militarily is welcome."
President Francois Hollande is meeting in Paris with British Prime Minister David Cameron on Monday, then going to Washington and Moscow later in the week to push for a stronger international coalition against ISIS.
French police have issued a new appeal to identify the third man involved in the attacks at the national stadium on Nov. 13.
National Police on Sunday posted a photo of the man on Twitter, appealing to the public for information that would help identify him. The man was among three people who died in the attacks outside the stadium.
British Prime Minister David Cameron is expected to outline his plan for combating ISIS this week as he moves toward seeking Parliament's approval for airstrikes on the group's Syrian strongholds.
The Sunday Times said Cameron will publish a seven-point plan on Syria this week that will include a blueprint for the nation's future.
Foreign Minister Philip Hammond has said Cameron will go to Parliament once he believes there is a consensus in favor of airstrikes.
Cameron expects the passage of a United Nations Security Council resolution calling for united action against ISIS to bolster his chances in Parliament.
Labour Party leader Jeremy Corbyn has warned about the risks of military intervention but said he will listen to the government's proposal.