Three presumed radical Islamists arrested last week were close to launch terrorist attack in the country, Paris prosecutor Francois Molin said Monday.

"The investigation before their arrest showed that they were training for making improvised explosive devices based on a jihadist radicalization, a glorification of Mohamed Merah, and an affirmed desire to go into action," Molin said.

"Even if we had no evidence of a precise plan, the messages exchanged by the participants suggested the timetable could be accelerated," he told reporters.

Last Thursday, French police arrested three men in Marignane, south France and found weapons and explosives at the home of one of them, according to the prosecutor.

The arrest of the Islamist suspects that were placed under formal investigation came at the first anniversary of al Qaeda-inspired young man Mohamed Merah's serial shooting that rocked France and left seven victims, including three kids.