BRUSSELS >> Belgian police launched more raids in Brussels and beyond early Monday, detaining five more people as they continued their hunt for a fugitive suspect in the Paris attacks.

In Paris, British Prime Minister David Cameron said he will ask for parliamentary approval for the U.K. to join airstrikes against Islamic State extremists in Syria.

The raids began late Sunday, capping a tense weekend that saw hundreds of troops patrolling and authorities hunting for one or more suspected extremists including Salah Abdeslam, a fugitive since being named a suspect in the Nov. 13 Paris attacks. Between Sunday night and midday Monday, 21 people were detained

The Belgian government kept the capital on the highest state of alert in the face of what it described as a “serious and imminent” threat, preventing a return to normal in the city that is also host to the European Union’s main institutions.

Federal prosecutor Eric Van Der Sypt said 19 raids were carried out Sunday in Molenbeek, home to many of the Paris attackers, and other boroughs of Brussels, and three raids were carried out in Charleroi. Abdeslam was not among those arrested. Van Der Sypt said no firearms or explosives were found.

Belgian Interior Minister Jan Jambon told the RTL network that Abdeslam “must have a lot of support on our territory. That’s why all these searches being conducted at the moment are important.”

Police fired two shots at a car that approached them as they searched a snack bar in Molenbeek, Van Der Sypt said. The vehicle escaped but was stopped later in Brussels, and a wounded person inside was arrested. It was not immediately known if the person was linked to the investigation into the Paris attacks.

Cameron and French President Francois Hollande, meeting in Paris, paid a quiet visit to the Bataclan concert venue, which saw the worst of the carnage in Paris. Hollande plans to meet later this week with Russian President Vladimir Putin, German Chancellor Angela Merkeld and then U.S. President Barack Obama in pursuit of a unified strategy in Syria.

Britain has been carrying out airstrikes in Iraq, but Cameron has long wished for an expanded mandate to include targets in Syria. But having lost a vote once two years ago, his government had been reluctant to even suggest a vote until it could be certain it would win.

Belgian authorities said more raids Monday in Brussels and eastern Liege yielded five more detentions.

The federal prosecutor said in a statement that a BMW sighting near Liege that had been rumored to contain Abdeslam had no links with the ongoing investigation.

Several of the Paris attackers had lived in Brussels, including Abdelhamid Abaaoud, the plot’s orchestrator who was killed Wednesday in a standoff with French police. Police issued a new public appeal for help in identifying the third attacker who was killed in the assault at the national stadium. They posted a photo of the man on Twitter, asking the public for information.

France has intensified its aerial bombing in Syria and Defense Minister Jean-Yves Le Drian said the aircraft carrier Charles de Gaulle, which has been sent to the Mediterranean, will be “operational” from Monday and “ready to act.”

France has extended a state of emergency which allows police raids, searches and house arrest without permission from a judge, for three months. On Saturday, it also extended a ban on demonstrations and other gatherings through Nov. 30, when a U.N. climate conference with more than 100 heads of state is scheduled to start.

The Islamic State group has claimed responsibility for the attacks in Paris that killed 130 people and wounded hundreds more; the suicide bombings in Beirut that killed 43 people and injured more than 200; and the downing of the Russian jetliner carrying 224 people in Egypt’s Sinai Peninsula. All happened within the past month.

Lori Hinnant in Paris, John-Thor Dahlburg and Raf Casert in Brussels and Danica Kirka in London contributed.