Twelve suspected members of a French Islamist cell linked to a grenade attack on a Jewish shop in Paris and suspected of planning further attacks were still in custody Monday, two days after their arrest.

The anti-terrorism prosecutor's office in Paris confirmed to dpa that a twelfth suspect of the so-called Cannes Group had been arrested Saturday evening in Torcy, about 30 kilometers east of Paris.

Of the 12 suspects, around half were arrested in the southern city of Cannes. They can be held for up to 96 hours without charge. Paris prosecutor Francois Molins said Saturday they faced charges of conspiring to commit terrorist acts.

The suspected leader of the cell was shot dead by police on Saturday during a raid on his apartment in the city of Strasbourg. Jeremie Louis-Sidney, 33, opened fire on police when they entered his apartment to arrest him. The police riposted, killing him.

Louis-Sidney's fingerprints were found on the grenade used in an attack on a kosher grocery store in the northern Paris suburb of Sarcelles on September 19.

The attack, which slightly injured a customer, caused only minor damage.

But the Jewish community was immediately alarmed, saying the attack fitted a pattern of rising anti-Semitism among a new generation of homegrown radical Islamists.

Most of the suspects arrested Saturday were young men from housing projects, with profiles similar to Mohamed Merah, the 23-year-old petty criminal from Toulouse who shot dead three Jewish children, a rabbi, and three soldiers before being shot dead by police in March.
 
The discovery during the weekend operation of a list of Jewish institutions in Paris has led to suspicion Louis-Sidney's group was planning further attacks.
 
On Sunday President Francois Hollande stepped up security around Jewish sites and vowed the state's "total mobilization" against terrorist threats.