BRUSSELS, Nov. 23 (UPI) -- Belgian authorities on Monday said they have charged another person in connection to the Nov. 13 terrorist attacks on Paris after numerous raids over the weekend rounded up many potential suspects.
Officials said the new suspect, who they did not immediately identify, was captured Sunday as police conducted nearly 30 raids in and around Brussels.
Authorities conducted the raids searching for the only known remaining attacker at large -- 26-year-old Belgium native Salah Abdeslam -- but did not locate him. The raids were also intended to disrupt another possible terrorist attack investigators believe may have been in the works.
Twenty nine raids and 21 people were rounded up over the weekend, officials said.
The unnamed suspect was charged with participating in activities of a terrorist group and a terrorist attack. Officials said 17 of the 21 people detained were released by Monday evening. No firearms or explosives turned up in the raids.
Abdeslam is being sought in a high-profile manhunt. He is a French citizen living in Brussels who police describe as armed and dangerous. Several of Abdeslam's friends in Brussels said he possibly may be traveling to Syria.
Belgium raised its terror alert on Saturday to the highest level due to what was called a "serious and imminent threat."
Belgian Prime Minister Charles Michel said the city of Brussels is under threat of attacks similar to those carried out in Paris more than a week ago. He said security forces will remain stationed in the city for at least another week.
Public transportation, universities and schools in Brussels remained closed Monday, as the city was a base of operations for the Islamic State militants who carried out coordinated attacks in Paris on Nov. 13, where at least 130 people died.
The Charles de Gaulle French military aircraft carrier will begin operations in the Mediterranean Sea on Monday against IS targets in Syria, officials said. Belgian schools are set to reopen Wednesday.