French authorities say they have arrested three adults and a minor for planning an imminent attack on security forces. The minor was previously convicted for trying to reach Syria to join the Islamic State armed group.
The four suspects were arrested Friday as part of an investigation into a terrorist conspiracy that the Paris prosecutor's office said was opened on 1 February.
“Four people are being held over a plan to carry out an extremely violent terror attack,” Interior Minister Christophe Castaner told reporters.
The prosecutor's office said France's internal intelligence service, the DGSI, was heading the investigation.
It said the arrests concerned “individuals suspected of preparing imminent violent acts, susceptible to target security forces”.
The prosecutor's office did not provide details about where the arrests were made or about the nature of the planned attack.
It said the minor had been arrested in February 2017 for trying to go to Syria to join the Islamic State (IS) armed group at age 15.
A juvenile court handed him a three-year prison sentence, of which two years were suspended. He was serving a probationary sentence at an educational facility at the time of the arrest.
A source close to the inquiry said the three others were known for common law offences.
France has been on high alert since a wave of jihadist attacks in 2015 that left more than 250 people dead. The IS urged followers to target soldiers and police in France.
Despite the collapse of the IS's self-proclaimed “caliphate” in Iraq and Syria last month, the risk of attacks inspired by the group remains high.
In late March, Paris police indicted two men, including one with psychiatric problems, on suspicion of planning an attack on a school or on police.