Six people were arrested in the Paris region on Monday in coordinated raids on members of a suspected radical Islamist cell allegedly planning terrorist acts on French soil, a source close to the investigation told the AFP news agency.

The suspects, aged between 22 and 38, were “all known to police for serious delinquency” and are being detained by the police anti-terrorist unit in the Paris suburb of Levallois, the news agency reported.

The members of the suspected Islamist cell include one man from Benin, another from the Comoros and four French nationals, a source close to the case said.

They are suspected of being involved in a hold-up of a branch of the Banque Postale in Seine-et-Marne in April “and apparently planning to commit other armed robberies”, the source close to the investigation said.

According to the anti-terror police investigators, the six “were planning to commit terrorist acts targeting well-known figures in France,” the source added, according to AFP.

The suspects can be held for up to 96 hours before being charged or released.

In March of 2012, terrorist Mohamed Merah killed three Jewish children and a rabbi in a shooting attack at the Otzar HaTorah school in Toulouse. Before that, he murdered three Muslim paratroopers of North African heritage. Merah was ultimately killed when he tried to flee a police raid on his apartment.

In March, France arrested three terrorists who were suspected of planning an attack around the anniversary of the attacks in Toulouse.

Police had found weapons and explosives in one suspect’s home in a town near Marseille. Police also intercepted communications between the men, suggesting they were planning on going into action.

Several weeks ago French police charged a 30-year-old man with supplying weapons used by Merah in his terror spree.

Last October, French police dismantled another Islamist cell, suspected of carrying out a grenade attack on a Jewish grocery store in a Paris suburb the previous month.

A French prosecutor branded that homegrown group of Islamist extremists as the biggest terror threat the country had faced since the Algerian-based GIA carried out a string of deadly bombings in the 1990s.

In May, Interior Minister Manuel Valls warned of a “global terrorist threat”, stressing that France was among the countries facing that threat, from both within and outside its borders.

“There is no longer a hermetic border between the interior and the exterior, the enemies within and those outside share in the global combat, to do harm to democracies in the name of radical Islamism,” he said, according to AFP.