Censor.NET reports citing The New York Times.
"Salah has not been arrested, no one has been arrested, the operations are continuing," Eric van der Sypt, a Belgian federal magistrate, said. "There is still an operation continuing right now in Molenbeek."
Mr. van der Sypt also said that news accounts that the authorities had homed in on a possible planner of the attack - Abdelhamid Abaaoud, an Islamic State affiliate now fighting in Syria - were premature.
Despite widespread reports in the news media "about the supposed identity of the jihadist Abdelhamid Abaaoud," Mr. van der Sypt said, "I can't confirm any of this - neither his name nor his implication in the attacks."
Also on Monday, French authorities announced they had conducted sweeping police raids around the country overnight and detained 104 people.
Under a state of emergency declared on Friday by President François Hollande, the police are empowered to conduct raids without a search warrant, and Mr. Cazeneuve said 168 such raids had taken place in 19 French departments, including the Paris region and in Lille, Lyon, Marseille and Toulouse. The police arrested 23 people and confiscated 19 weapons, including 19 handguns, eight long guns and four heavy weapons, as well as computer hardware, mobile phones and narcotics.
In one home in the Rhône department, Mr. Cazeneuve said, the police found a Kalashnikov assault rifle, three automatic pistols, ammunition and bulletproof vests. Officers obtained a warrant to search the home of the parents of one suspect, where they found several automatic pistols, ammunition, police armbands, military clothing and a rocket-launcher.
Mr. Cazeneuve said that the investigation on the attacks in Paris was "making quick progress" but that the threat of terrorist attacks "remains high." Six attacks on French territory have been foiled or avoided since the spring, Mr. Cazeneuve said.
The raids in both countries were carried out as the authorities continued a manhunt for Mr. Abdeslam, 26, who is believed to have been a central figure in the attacks, along with two brothers, Mohamed and Ibrahim. Salah Abdeslam was stopped by the French police early Saturday as he drove on a highway into Belgium, but he was let go when his papers appeared to be in order.
Belgian national broadcaster RTL earlier reported that the man arrested in a raid in the Molenbeek area of Brussels on Monday morning was Salah Abdeslam.
The RTL also published photos from the scene:
Heavily armed police officers wearing balaclavas surrounded the Molenbeek neighborhood of Brussels on Monday in a manhunt for Salah Abdeslam, who is believed to have helped carry out the Paris terrorist attacks on Friday with his two brothers.