One of the three attackers had turned himself in to the police this morning.
Two armed men suspected to have gunned down 12 people at the Paris office of French satirical weekly Charlie Hebdo on Wednesday, have been "located" in north France, news agency AFP reports quoting sources.
The two are suspected to be Cherif Kouachi, 32, a known jihadist convicted in 2008 for involvement in a network sending fighters to Iraq, and his 34-year-old brother Said. Both were born in Paris.
Masked, black-clad gunmen had burst into the offices of the magazine on Wednesday morning, killing some of France's most outspoken journalists and two policemen, before jumping into a car and escaping.
A third suspect, Hamyd Mourad, 18, had turned himself in to the police about this morning.
Seven people were detained in the hunt for the brothers, Interior Minister Bernard Cazeneuve said on Thursday. "Seven people," Cazeneuve said on French radio when asked how many people were being held and questioned over the attack - the bloodiest in France in half a century.