PARIS — An attacker who stabbed and killed a 29-year-old in central Paris on Saturday night was a naturalized Frenchman born in Russia’s Chechnya region in 1997, judicial sources said on Sunday.

The unnamed assailant shouted “Allahu Akbar” (God is greatest) as he also wounded four others, among them a Chinese and a Luxembourg citizen, before police shot him dead, officials said.

The attack took place in the busy Opera district known for its many restaurants, cafes and the Palais Garnier opera.

It was one of a succession in France in which more than 240 people have died since January 2015, keeping the country on high alert.

France is part of a US-led coalition fighting Daesh (the so-called IS) in Syria and Iraq and has thousands of soldiers in West Africa, where al Qaeda-linked militants are active.

The 21-year-old assailant had been categorized as “fiche S” since 2016, government spokesman Benjamin Griveaux said — a designation officials use to flag people who may be a threat to national security.

He became French when his mother obtained citizenship in 2010, Griveaux said in a joint interview with broadcasters LCI and RTL and newspaper Le Figaro.

He rejecting criticism from some politicians that the government was not doing enough to stem such attacks, adding: “Zero risk does not exist.”

Daesh claimed responsibility for the attack via its Amaq news agency, but provided no proof.

President Emmanuel Macron said France would “not yield an inch to the enemies of freedom,” and praised police for “neutralizing the terrorist”.

A judicial source said the assailant’s parents were being held for questioning.

Police union representative Rocco Contento told Reuters the attacker had rushed at police shouting “I will kill you, I will kill you!” after stabbing bystanders.

He was then shot by the officers.

“It was scary,” said Emma Klibbe, a 32-year old Australian who was waiting to get into a nearby restaurant and saw a man walk by who was injured in the attack.

“We heard someone shout and then a woman screamed ‘run inside!’ We ran inside and hid under the table,” said Klibbe, who teaches English in Paris. “We all just hid under tables for quite a while. We were not allowed to go outside.”

The four people wounded were out of danger, Interior Minister Gerard Collomb said.

A picture seen by Reuters showed a bare-chested and bearded young man dressed in black sweatpants lying on the ground and being helped by emergency services. A source said he was the attacker.

The judicial source said the person killed, who authorities have not officially identified, was a man aged 29.

The deadliest of the attacks that have hit France over the past three years occurred in Paris in November 2015, when 130 people were killed.

In October, in an incident similar to Saturday’s, a man stabbed two young women to death in the port city of Marseille before he was shot dead by soldiers.

France has suffered a series of major terror attacks including the massacre at the satirical newspaper Charlie Hebdo, the November 2015 attacks that killed 130 in Paris, and the 2016 Bastille Day truck attack in Nice that killed more than 80.

There have also been a string of less deadly but frequent attacks by lone wolf militants wielding knives or guns. Most of the attacks have either been claimed by Daesh or been carried out in their name.

A state of emergency put in place just after the 2015 Paris attacks was lifted in October when Macron’s centrist government passed a new law boosting the powers of security forces.