French police have arrested a 15-year-old boy suspected of plotting to carry out terror attacks in the country.
The teenager was detained in Paris and is believed to have links with a French member of so-called Islamic State (IS), Rashid Kassim.
Investigators say the boy was under surveillance since April and had contacted IS through social media.
Another boy, also 15 and also suspected of links to Kassim, was arrested in Paris on Saturday.
French officials say he is a key instigator who uses encrypted forums to direct recruits on how and where to carry out attacks in Europe.
French Interior Minister Bernard Cazeneuve said the arrests were part of efforts to pinpoint vulnerable citizens in France who have been targeted with "calls to carry out killings, led by a certain number of actors in Syria".
The arrests this week follow the detention of three women, including a 19-year-old, who had allegedly wanted to attack a Paris railway station using a car laden with gas cylinders.
Kassim, who has appeared in propaganda videos in Iraq or Syria, is thought to have planned at least four terror attacks in France since June.
An amateur rapper and youth leader from Roanne, north-east of France's second city Lyon, Rashid Kassim is thought to have been radicalised either over the internet or on a trip to Algeria in 2011.
He fell out with his local Muslim community and left France with his wife and three children for Egypt the following year. Little was known of him until he appeared in a brutal IS propaganda video after the Bastille Day lorry attack on Nice in July.
In the video, he murders two Syrian prisoners and threatens similar attacks on the streets of France by French citizens. Also known as Ibn Qassim, his focus is recruiting young French would-be jihadists, using social media and chat groups.
He has urged his 300 followers on Telegram to carry out what prosecutors term "terrorisme de proximite" (local terrorism).
French Prime Minister Manuel Valls has said the country's security services are foiling terror plots and dismantling militant networks "every day".
France has been under a state of emergency since IS attacks on Paris in November killed 130 people in what President Francois Hollande called an "act of war".