PARIS (Reuters) - French authorities said on Wednesday they had rooted out an "extremely dangerous terror network" after uncovering weapons and bomb-making materials in their investigation of suspected radical Islamists detained at the weekend.
Paris prosecutor Francois Molins said a dozen people arrested on Saturday would be held for a further 24 hours after chemicals used to make explosives were found at a garage in the Paris suburbs belonging to one of them.
The raids were triggered by a grenade attack on a kosher grocery store outside Paris last month, and have further unsettled Europe's largest Jewish community, which was shaken when an al Qaeda-inspired gunman shot dead three Jewish children and a rabbi in Toulouse in March.
"We are clearly confronted with an extremely dangerous terror network," Molins said in a statement to the media. "It is essential to extend their stay in custody."
Investigators carried out overnight searches of garages in Torcy, a town in the eastern suburbs of Paris, after Saturday's raid ended with police shooting dead an Islamist suspect linked to the grenade attack and arresting 11 others.
Another suspect was subsequently arrested, bringing the total to 12.
Police on Saturday found a list of local Jewish groups at the home of one of the suspects. Molins said a search of the suspect's garage had revealed a shotgun, a revolver, bags of potassium nitrate, sulphur and a pressure cooker.
"These are all products used to make what we call improvised explosives," he said.
JEWS ON EDGE
While Britain and Spain have suffered coordinated Islamist militant attacks on their capitals in the last 10 years, France had not seen an attack with mass casualties on its soil since 1995, when an Algerian Islamist group bombed the underground Metro network and other sites in the capital.
Molins said the detention of the dozen suspects could be extended by a further six days if necessary.
France's Jewish community has been on edge after a series of attacks in recent months. In the worst incident, 23-year-old Mohamed Merah, seemingly acting alone, killed three soldiers in two separate attacks before shooting dead three children and a rabbi outside a Jewish school in Toulouse.
Interior Minister Manuel Valls said there were several hundred radical Islamists in France capable of acts of terrorism, and that its prisons were breeding radicalism.
President Francois Hollande promised on Sunday to step up security around synagogues and said the government would soon present legislation to parliament that would allow police to arrest people believed to have been involved in terrorism-related activity outside France.
The Socialist government is taking a hard line on terrorism, saying no act will be tolerated, as it tries to avoid a repeat of the bloodshed in Toulouse.
The incident prompted authorities to raise the terrorism alert in the Toulouse region to "scarlet", the highest level - the first time this had been done in France.
That was later reduced to "red", where it had been since coordinated attacks on the London transport system in 2005.
(Reporting by Catherine Bremer and Alexandria Sage; Editing by Kevin Liffey)