A French teenager linked to an "Islamic State of Iraq and the Levant" (ISIL) element suspected of instigating several attacks in France was arrested in Paris on Wednesday (September 14th) for allegedly offering to carry out a strike, AFP reported.

The youth was in touch with French extremist Rachid Kassim, who is suspected of ordering or inciting the killing of a police couple in their home in June and the murder of an elderly priest in a Normandy church in July, police sources said.

The arrest comes two days after a 15-year-old from eastern Paris was charged with conspiring to commit terrorist acts after writing on Telegram, an encrypted messaging app, of his plans to commit a stabbing, sources said.

He too had been in contact with Kassim, who has appeared in several Telegram videos made in Syria and Iraq urging attacks in France.

Interior Minister Bernard Cazeneuve said Wednesday that the intelligence services were "working harder than ever" to prevent assaults incited by "a number of characters in Syria who used encrypted methods to call on young people to carry out attacks".

French Prime Minister Manuel Valls on Sunday said the terror threat was at a "maximum" and that the authorities were foiling attacks and smashing extremist networks "every day".