Paris (CNN) The person who stabbed five people in Paris on Saturday night, killing one, yelled the Arabic phrase "Allahu Akbar," meaning "God is great," during the attack, city prosecutor François Molins told reporters at the scene.

Authorities have opened a terrorism investigation, he said.

Four people were wounded during the knife attack in the touristy 2nd arrondissement, or district, of Paris. It happened around 9 p.m. (3 p.m. ET) , a time when streets and sidewalks were filled with people.

Two of the victims were gravely wounded and two others were lightly injured, police said.

Investigators look through the scene of the attack Saturday night.

The attacker, who French President Emmanuel Macron called a terrorist, is dead, according to police.

Read More</s>Media playback is unsupported on your device Media caption French police at the scene of the attack in Paris

A knifeman has killed one person and wounded four in a suspected terror attack in central Paris, French officials say.

The attacker was then shot dead by police in the Opéra district. Witnesses say they heard him shout "Allah Akbar".

So-called Islamic State (IS) later said one of its "soldiers" had carried out the attack on Saturday evening.

Judicial sources told French media the attacker was a man born in 1997 in the southern Russian republic of Chechnya.

The sources said his parents had been held for questioning.

Interior Minister Gérard Collomb said the victim of the attack was a 29-year-old man, but gave no further details.

French President Emmanuel Macron tweeted (in French): "France has once again paid in blood, but will not give an inch to the enemies of freedom."

How did the events unfold?

The attacker began stabbing passers-by at about 21:00 local time (19:00 GMT) on the rue Monsigny.

Eyewitnesses described him as a young man with brown hair and a beard, dressed in black tracksuit trousers.

The man tried to enter several bars and restaurants but was blocked by people inside. Police arrived at the scene within minutes.

They first tried to stop the assailant with a stun-gun before shooting him dead.

An eyewitness, named as Gloria, told AFP news agency: "We didn't know what was going on, we were quickly moved inside the bar, I went outside and I saw a man lying on the floor."

Image copyright AFP Image caption Forensic officers have been examining the scene of the attack

Jonathan, a waiter at a local restaurant, told AFP: "I saw him with a knife in his hand. He looked crazy."

He said a woman the attacker had stabbed ran into into the restaurant bleeding. The assailant tried to follow her inside, but was fended off and finally fled.

Two of the wounded in the attack are in a serious condition but do not have life-threatening injuries.

Later in the evening the IS group said it was behind the attack, in a brief statement posted on its news outlet.

How did French authorities react?

The anti-terrorism unit of the Paris prosecutor's office has launched an investigation.

Prime Minister Edouard Philippe said police were on the scene five minutes after an emergency call and the attacker was killed "less than nine minutes later".

Mr Collomb praised police for their "cool response". He said his first thoughts were "with the victims of this heinous act".

Paris Mayor Anne Hidalgo tweeted (in French): "Tonight, our city was bruised."

"I want to tell them that all Parisians are on their side," she added.

Image copyright AFP Image caption The Opera district is renowned for its nightlife

How has France been countering security threats?

France has been on high alert following a series of attacks. More than 230 people have been killed by IS-inspired jihadists in the past three years.

The deadliest violence occurred on 13 November 2015, when gunmen and suicide bombers struck various venues in Paris almost simultaneously - killing a total 130 people.

After winning last year's elections, President Macron pledged that fighting Islamist terrorism would be his top foreign policy priority.

Defeating IS in Iraq and Syria must go hand-in-hand with anti-terror measures in Africa, he said.</s>A man armed with a knife in Paris has killed at least one person and injured several others before being shot dead by police, according to French media.

The attack on Saturday reportedly took place near the main opera house in the French capital.

The Paris prefecture said a person who carried out the knife attack was overpowered by police, without giving any more details.

Citing sources close to official investigations, AFP news agency said that two people, including the attacker, were killed and several were injured.

BFM TV also said that one person was killed in the attack, while the assailant was shot dead by police.

In a message on Twitter, Interior Minister Gerard Collomb praised the "cool and quick reaction of the police forces who neutralised the attacker".

There was no immediate information about the suspect's motive.</s>01:04 (GMT+4) A man killed a passer-by in a knife attack in the heart of Paris and injured four others before being shot dead by police, French authorities said, Reuters reported.

“A person attacked five people in the second district of Paris. Police intervened immediately,” Pierre Gaudin, a senior official at the Paris prefecture, told reporters.

“The individual died. Another person, seriously injured (by the attacked) died from their injuries.”

The Paris prefecture had earlier said a person had carried out a knife attack in the second arrondissement - or district - of the French capital. Paris’ opera and landmark retail stores are located in that area.</s>A knife-wielding attacker has killed one person and injured four in the centre of Paris before being killed by police.

Paris police tweeted that the attack happened Saturday evening in the 2nd arrondissement or district of the French capital.

Police said the person armed with the knife targeted five people, killing one and seriously injuring two and lightly injuring the other two.

They said the attacker died.

Interior minister Gerard Collomb said the alleged attacker was “neutralised” by police and praised officers for their actions

The identity of the attacker and the reason for it are unclear.

Paris has been under higher security in recent years after a string of deadly Islamic extremist attacks.</s>A knife-wielding attacker has killed one person and injured four in the centre of Paris before being killed by police, in what is being treated as a terror attack.

French President Emmanuel Macron tweeted his praise for police who "neutralised the terrorist" and his thoughts for the victims.

Mr Macron said: "France is once again paying the price of blood, but will not cede an inch to enemies of freedom."

Counter terrorism authorities are leading the investigation into the attack.

The Islamic State group's news agency claims that a man who stabbed five people in Paris was a "soldier" of the extremist movement.

The Aamaq news agency said in a statement early on Sunday that the assailant carried out the Saturday night attack in response to the Islamic State group's calls for supporters to target members of the US-led military coalition squeezing the extremists out of Iraq and Syria.

Paris police tweeted that the attack happened in the 2nd arrondissement or district of the French capital.

Police said the person armed with the knife targeted five people, killing one and seriously injuring two and lightly injuring the other two.

They said the attacker died.

Interior minister Gerard Collomb said the alleged attacker was "neutralised" by police and praised officers for their actions

Paris has been under higher security in recent years after a string of deadly Islamic extremist attacks.</s>The Latest on a knife attack in Paris (all times local):

French authorities say a knife-wielding assailant killed one person and injured four in the center of Paris before being killed by police.

Paris police tweeted that the attack occurred Saturday evening in the 2nd arrondissement or district of the French capital. Police said the person armed with the knife targeted five people, killing one and seriously injuring two and lightly injuring the other two.

Paris police said the attacker died. Interior Minister Gerard Collomb said the alleged attacker was "neutralized" by police and praised officers for their actions.

The identity of the attack suspect and reason for the attack are unclear.

Paris has been under higher security in recent years after a string of deadly Islamic extremist attacks.

French authorities are denouncing a knife attack in central Paris that French media say left two dead including the assailant.

The Paris police said the attacker was subdued by officers during the stabbing attack in the 2nd arrondissement or district of the French capital Saturday. The police said the attacker was armed with a knife, but gave no other details.

French media reported that two people are dead, and BFM television said one of them is the alleged attacker. The motive or reason for the attack was unclear.

Interior Minister Gerard Collomb denounced the "odious attack" in a tweet. Paris has been under higher security in recent years after a string of deadly Islamic extremist attacks.</s>French authorities have condemned a knife attack in central Paris that the country's media say left two dead including the attacker.

The Paris police said the attacker was subdued by officers during the stabbing attack in the 2nd arrondissement or district of the French capital on Saturday.

Paris Police tweeted: "An attack on five people in the 2nd arrondissement of Paris by an individual armed with a knife: One victim has died, two are seriously wounded and two are injured slightly. The assailant is dead."

The identity of the attacker and the person's motives are unclear.

French police asked the public not to spread rumours about the attack before the facts became clear.

"Please only share information coming from a trusted source," the police tweeted.

Interior minister Gerard Collomb condemned the "odious attack" and said the alleged attacker was "neutralised" by police and praised officers for their actions.

Paris has been under higher security in recent years after a string of deadly Islamic extremist attacks.</s>A knife-wielding suspect who slashed five people, killing one, in central Paris on Saturday night -- before being slain by French authorities -- has been claimed as a “soldier” of ISIS, the extremist group’s news agency said.

The Islamic State group claimed responsibility for the knife attack, saying it was in response to the terrorists' calls for supporters to target members of the U.S.-led military coalition squeezing extremists out of Iraq and Syria, the Aamaq news agency said in a statement.

"We are closely monitoring the incident in Paris, and understand the authorities have initiated a terror probe," a State Department spokesperson told Fox News. "Our thoughts are with the family and friends of those affected. We refer you to the local authorities for further information.

"We stand ready to provide all possible consular assistance should we become aware of any affected U.S. citizens. U.S. citizens in the France are strongly encouraged to directly contact concerned family members in the United States to advise them of your safety.‎"

The still unidentified suspect carried out the stabbing attack Saturday evening in the 2nd Arrondissement of Paris, north of the Seine River, which ultimately led to two casualties, including the attacker. Two other people were seriously injured and two more were slightly injured.

Counterterrorism authorities were called in to lead the investigation after Prosecutor Francois Molins told reporters that witnesses heard the suspect shouting, "Allahu Akbar" -- "God is great" in Arabic.

The assailant, after attacking bystanders with a knife, rushed at police, shouting “I will kill you, I will kill you!” police union representative Rocco Contento told Reuters.

The attacker was then shot by officers and later confirmed dead, Paris police said.

Witnesses reportedly said that the police first tried to use a stun gun on the attacker, but when that failed, they fired two shots, the BBC reported, citing France24.

Police did not confirm local media reports that the suspect had been fatally shot.

The attack took place in a popular neighborhood near Paris’ famed Opera Garnier. People were asked to evacuate nearby buildings.

Police said that the suspect targeted the five people.

In a tweet sharing his condolences, French President Emmanuel Macron labeled the attacker a “terrorist.”

“All my thoughts go to the victims and the wounded of the knife attack perpetrated tonight in Paris, as well as to their relatives. I salute on behalf of all the French the courage of the policemen who have neutralized the terrorist,” a translation of his tweet said.

“France once again paid the price of blood but did not give an inch to the enemies of Freedom,” Macron said in another tweet.

France's BFM television interviewed an unnamed witness in a restaurant who said a young woman was at the entrance when "a man arrived and attacked her with a knife." A friend came to her aid and the attacker left, "hitting on all the doors, all the shops," the witness told BFM. He turned onto another street, and everyone scattered, the witness said.

"I was having a drink with friends and we heard a boom," a witness named Gloria, who had been in a nearby bar, recounted on Saturday night. She said she went outside to see what happened and "I saw a guy lying on the ground."

Another witness described leaving the opera house and being told to go back inside because of the attack.

"My first thoughts are with the victims of this odious act," a translation said.

Collomb said the lives of the injured people were no longer in danger.

Paris has been under elevated security in recent years after a string of deadly Islamic extremist attacks.

The Associated Press contributed to this report.

Aggression in Paris: I salute the cold blood and responsiveness of the police forces who neutralized the assailant. My first thoughts are with the victims of this heinous act.

Aggression in Paris: I salute the cold blood and responsiveness of the police forces who neutralized the assailant. My first thoughts are with the victims of this heinous act.</s>CNN — One person is dead and eight others were wounded during a Saturday night knife attack in Paris, CNN affiliate BFM-TV reported.

France’s Interior Ministry tweeted that the attacker was neutralized by police. It was unclear whether the deceased person reported by BFM was the attacker.

Police have said the situation is under control.

BFM also said there is no known motivation for the attack at this time.

Developing story – more to come
One person is killed and four wounded in a knife attack in Paris, France. The attacker is killed by police.