France is tracking hundreds of people believed to belong to possible sleeper cells for terror organizations like al-Qaida or the Islamic State group, the country's top security official said.

In an interview with The Associated Press, Interior Minister Bernard Cazeneuve laid out what has become an increasingly urgent question for European intelligence services: How to trace the moment when someone transforms from a disgruntled criminal or a disaffected citizen into a terrorist, and how to block those first steps toward radicalization.

"Four hundred targets have been identified by our intelligence services that are more or less sleeper cells, affiliated or in relation with al-Qaida-type organizations, that can strike like the Kouachi brothers," Cazeneuve said in an interview late Monday ahead of his Wednesday departure.

Said and Cherif Kouachi were French-born brothers who killed 12 people in Paris on Jan. 7 when they stormed the satirical newspaper Charlie Hebdo. They were shot dead by police in a confrontation two days later.

Cazeneuve said he wants new measures to give intelligence services more leeway to monitor suspects' electronic communications. He is heading to the United States this week to try and persuade Internet giants to step up and help stem extremists' ability to use propaganda videos to recruit and indoctrinate new followers.

Facebook, Twitter, Apple and Google - all major vectors for increasingly sophisticated jihadi clips targeting potential followers in the West - will be among his stops in Silicon Valley.