France's prime minister called for the country's state of emergency be extended for another three months on Thursday, warning that there "could also be a risk" of an attack using chemical or biological weapons.
"Terrorism hit France not because of what it is doing in Iraq and Syria ... but for what it is," Manuel Valls told the lower house of parliament. "We know that there could also be a risk of chemical or biological weapons ... We must not rule anything out."
Valls also said that those convicted of terrorism should be stripped of their French citizenship.
He was unveiling a security bill in the wake of the deadly Paris attacks that left nearly 130 dead and hundreds injured.
"This bill will also encourage the closing of mosques if they become too radical," Valls said. "This bill is the answer for the right of a free country facing chaos."
The measures were aimed at reducing the threat of attacks by Islamist extremist groups including ISIS, which has conquered swaths of Iraq and Syria and claimed responsibility for Friday's attack.
"Some have repented but we are not sure," he said. "We need to be tougher at the borders for those coming back from Syria."
French authorities declared a state of emergency immediately after the attacks, and security forces have conducted hundreds of raids. On Wednesday, the French government announced that it would not allow planned marches to go ahead on Nov. 29 and Dec. 12 during international climate talks to be held Paris due to security concerns.