BRUSSELS — Belgian authorities on Thursday announced the arrest of a 10th person in connection with last month’s bloodbath in Paris and said six others had been detained and questioned over a suspected plot to stage new attacks in Brussels during the holidays.

Law enforcement officials said there is no known connection between the two investigations, but they highlight the role of Belgium as a hotbed of Islamic radicalism in Europe.

Authorities said a Belgian national born in 1993 and identified only as Ayoub B. has been charged with terrorist murder and participation in the activities of a terrorist group for his suspected involvement in the Nov. 13 attacks in Paris, claimed by the Islamic State group.

The man was detained Wednesday following a search in the Molenbeek neighborhood of Brussels, where some of the Paris attackers lived, including suspected ringleader Abdelhamid Abaaoud.

Nine people in Belgium had already been arrested in connection with the attacks, in which 130 people lost their lives and hundreds more were injured.

The Federal Prosecutor’s Office also said six people were brought in for questioning and seven searches carried out Thursday morning in various Brussels-area locations in connection with a suspected plot to stage extremist attacks over the holidays on police, soldiers and popular sites in the Belgian capital.

On Thursday evening, the office announced that three of the people questioned had been released, and that the other three would be kept in detention for up to 24 additional hours. It said no further details would be made public, and that the investigation was continuing.

Computer materials, cellphones and equipment for airsoft, a sport that uses replica firearms to fire non-metallic pellets, were confiscated in the Thursday searches, prosecutors said. Previous searches in the case led to the impounding of military-style training uniforms and IS propaganda material, they said.