PARIS -- France's government hardened its position toward dual-national terrorism convicts Wednesday, saying they deserved to have their citizenship revoked as part of constitutional changes upholding the state of emergency imposed after the Nov. 13 attacks in Paris.

In a speech presenting the proposed changes, Prime Minister Manuel Valls also left open the possibility of prolonging the state of emergency beyond its current three-month window, describing an "unparalleled extraordinary situation, an unprecedented fight" that France is facing.

The government's proposal came under immediate criticism from human rights groups, including the French anti-racism organization MRAP and Amnesty International. But Marine Le Pen, leader of the far-right National Front, sent out a tweet saying it was the first effect of her party's surge in support in France's recent regional election.

The Paris attacks, which left 130 dead and hundreds wounded, were carried out in the name of the Islamic State group largely by French and Belgian extremists. Afterward, the state of emergency allowed security forces to impose house arrests and carry out searches without a warrant.

Valls said in 40 days, 2,900 searches had netted 443 weapons, including 40 military-grade arms.

In all, 1,000 people have left from France to join extremists in Syria and Iraq, Valls said, by far the largest contingent from Western Europe.

"We know that the fighters are often grouped according to their language, to train and prepare actions on our soil," he said.

This appears to have been the case for at least some of the Nov. 13 attackers, who included French-speaking men who had left to fight for Islamic State.

The plan to revoke citizenship for terror convicts has caused fissures in the Socialist government. But France's justice minister, Christiane Taubira, who had said she was opposed to the measure, was on stage next to Valls when he announced it.

"It is a highly symbolic measure," Valls said. "This is a strong punishment that the nation is lawfully entitled to impose upon someone who commits the ultimate betrayal."

Human rights groups said the plan was a longtime favourite of the far-right.

"This unfortunate plan, an old idea of the extreme right, validates the idea that there are two categories of French, even in crime, some who are a little less French than others before the law," MRAP said in a statement.