Police in Belgium have conducted more raids, detaining five more people as they continue their hunt for a fugitive suspect in the Paris attacks.
Belgian authorities said it had carried out five raids in the Brussels area and two around the eastern city of Liege early on November 23.
Belgian authorities earlier announced they had detained 16 people in raids in Brussels and Charleroi late on November 22.
France, meanwhile, launched its first combat missions against the Islamic State (IS) group from its Charles de Gaulle aircraft carrier, which was deployed to the Mediterranean Sea in the wake of the deadly attacks in the French capital.
The attacks, claimed by Islamic State militants, left 130 people dead and hundreds wounded.
In Paris, Britain's Prime Minister David Cameron accompanied French President Francois Hollande in a visit on November 23 to the Bataclan concert hall, where 90 people died in the bloodiest of the Paris terrorist attacks.
Cameron said he will ask for parliamentary approval for the United Kingdom to join air strikes against Islamic State extremists in Syria.
Hollande vowed to continue strikes against the IS group in Syria and Iraq, saying, "We will intensify our strikes, choosing targets that will do the most damage possible to this army of terrorists."
Meanwhile, France's military announced that the newly-deployed Charles de Gaulle aircraft carrier had launched air strikes against IS targets in the Iraqi cities of Ramadi and Mosul.
The nuclear-powered aircraft carrier, deployed in the eastern Mediterranean, has 26 fighter aircraft, tripling France's capacity to carry out strikes.
It is accompanied by two French frigates, a supply ship, and a submarine, as well as a Belgian frigate and a British destroyer.
Eric Van Der Sypt, a spokesman for Belgium’s federal prosecutor, said that a key suspect in the case, French-born militant Salah Abdeslam, was "not among those arrested during the searches" on November 22.
Belgian officials would not release details about the identities of those detained, nor specific charges against the suspects, "in the interest of the investigation" while security operations are continuing.
The late night raids included 19 house searches in the Brussels region as well as three house searches in Charleroi, a city in southern Belgium's Wallonia region.
Officials said they did not find any guns or explosives during the searches.
However, Van Der Sypt said that during a search of a snack bar in the Sint-Jans-Molenbeek district of Brussels, a driver rammed his vehicle “into the police” and sped off.
He said police fired two shots at the fleeing vehicle, and that the driver -- "a man who was hurt" -- was "intercepted later in Brussels" and placed under arrest.
Van Der Sypt said: "For the time being, we cannot confirm if there is a relation between the ongoing investigation and this arrest."
Brussels remains on its highest alert level as a result of what Belgium's prime minister has called a "serious and imminent" threat of coordinated, multiple attacks by Islamist extremists.
The level four security alert for Brussels was declared on November 21.
Earlier media reports suggested the heightened terror threat was linked to concerns Abdeslam, a 26-year-old who is thought to be one of the ringleaders of the Paris attacks, is hiding in the Brussels area.
But Interior Minister Jan Jambon said on November 22 that the current threat was greater than that posed by Abdeslam.
"It is a threat that goes beyond just that one person," Jambon told Flemish broadcaster VRT.
"We're looking at more things. That's why we've put in place such a concentration of resources."
Prime Minister Charles Michel told reporters in Brussels on November 22: "What we fear is an attack similar to the one in Paris, with several individuals who could also possibly launch several attacks at the same time in multiple locations.”
He said possible targets are commercial centers, shopping streets, or public transport.
The city's metro system will stay closed and all schools and universities will be shut on November 23, Michel said following a meeting of the national security council to review the situation in the country.
For the rest of the country, a threat level of three on a four tier scale would stay in place, Michel said.
He said a new evaluation of the situation would be made on November 23 in the afternoon while adding that and everything was being done to return the city to normal as quickly as possible.
The Belgian capital’s metro network was closed during the weekend and major events like soccer matches were cancelled.
Extra security has been deployed on trains, in railway stations, and at airports.
The mayor of Brussels also has ordered restaurants and cafes across the city to close, along with shopping centers and public buildings.
Islamic State militants claimed responsibility for the Paris attacks that killed 130 people.
Brussels has been at the center of investigations since it emerged that two Paris suicide bombers had been living in Belgium.
Another alleged ringleader of the Paris attacks, 28-year-old Abdelhamid Abaaoud, was a Belgian of Moroccan origin.
With reporting by AFP, AP, and Reuters