PARIS (AP) — The Paris prosecutor’s office says several people, including a minor, have been arrested on suspicion they were preparing an attack possibly targeting French security forces in the near future.

They were arrested Friday as part of an investigation opened on Feb. 1 for terrorist conspiracy, the office said Monday, without providing details about the number of people involved or where they were arrested.

French broadcaster BFM TV said four men were being held by police.

The prosecutor’s office said the minor had previously been arrested in February 2017 at the age of 15 as he was trying to go to Syria to join the Islamic State group.

He had been sentenced by a juvenile court to a three-year prison sentence, of which two years were suspended.