By Chine Labbé
PARIS (Reuters) - Anti-terrorism police arrested 10 people across France on Monday in a sweep aimed at disrupting a suspected jihadist network sending young fighters to Syria, the Paris prosecutors' office said.
The arrests were mostly carried out in the cities of Toulouse and Le Havre as well as Paris, the office said.
BFM-TV reported the early morning raids stemmed from an investigation launched last year after a Turkish family concerned about the behavior of their son alerted authorities.
The investigation also targeted four people in prison linked to the presumed network, police told Reuters.
"For several years, these jihadist networks have represented an unrivalled threat," Prime Minister Manuel Valls said during a visit to Dijon.
"We've been working for two years to respond to this threat, to dismantle these networks with the work of the police."
Authorities say 1,132 French nationals have been linked to fighting in Syria or Iraq, more than any other Western nation. That number includes those either currently in Syria or Iraq, those in transit, and those who have returned.
In November, a 22-year-old French convert to Islam, Maxime Hauchard, appeared in a video of the beheading of a U.S. aid worker.
(Reporting By Alexandria Sage and Chine Labbé; Editing by Dominic Evans)