French police have uncovered bomb-making material during a probe into a group of Islamic extremists detained at the weekend for allegedly targeting Jews, prosecutors said Wednesday.
Describing the group as a serious threat, Paris prosecutor Francois Molins said the detention of the 12 suspects pending charges would be extended beyond the usual four-day maximum to at least a fifth day.
"We are clearly and objectively facing an extremely dangerous terrorist cell," Molins said in a statement, adding that it was necessary to "avoid the risk of a terrorist attack in France".
He said "components useful for bomb-making" had been found overnight during police searches of buildings in the eastern Paris suburb of Torcy, where two of the suspects were detained on Saturday.
Among the components found were bags of potassium nitrate, sulphur, saltpetre, pressure cookers and headlight bulbs, "all products or instruments useful in the making of what we call improvised explosives," Molins said.
A shotgun and handgun were also found, he said.
The 12 suspects were detained at the weekend on suspicion of involvement in a grenade attack on a Jewish grocery store last month and of planning other anti-Semitic attacks.
The suspected leader of those detained, 33-year-old Jeremie Louis-Sidney, was shot dead Saturday after he opened fire on officers seeking to arrest him in a dawn raid at his home in Strasbourg