In a terrorist attack at a church in Nice on the Côte d'Azur, a man armed with a knife killed three people-two women and a man.

The killings took place on Thursday at 9 a.m. inside the Basilica of Notre-Dame in the city center.

It was reported that one of the victims was a 70-year-old woman who was beheaded in a church. A man was the second victim, believed to be the churchwarden. A woman was critically wounded in her 40s and managed to run from the church but died from her injuries.

The scene was described by the police as a 'vision of horror.' The national anti-terrorism prosecutor said that an investigation into "killings linked to a terrorist organization" had been opened.

The assailant was shot by police in the shoulder and taken to the hospital.

The mayor of Nice, Christian Estrosi, said that while he was being arrested and handcuffed by police, the man had said "Allahu Akbar" several times.

He said he had "decapitated" one of the female victims, but he had no details of how the two others were killed.

"Inside the church, we've got two people killed ... and a third person who was in a bar facing the church where she took refuge," Estrosi said. "Enough is enough ... we must remove from our territory this Islam-fascism."

There were also reports on Thursday that police shot dead a man carrying a knife and threatening passersby in the street in Avignon.

At 11:15 am, just over two hours after the Nice attack, the shooting took place. After the man reportedly threatened them, police opened fire.

Two weeks ago, during a debate on free speech, a history teacher, Samuel Paty, 47, was decapitated outside his secondary school after showing his class caricatures, including one of the prophet Muhammad.

His assassination prompted French President Emmanuel Macron to pledge a crackdown on Islamist extremism, including the shutdown of mosques and other organizations accused of inciting violence and radicalism.

The knifeman entered the church in Nice on Thursday at 9 a.m. and three people were killed within 10 minutes, one of them a sacristan (churchwarden). At 9:10 am, he was "neutralized" by police in the church.

A witness named David, who runs the Brioche Chaude restaurant across from the church, told BFMTV that the police had been alerted.

When a man came in, I was selling croissants and he said to me, 'Sir, there is a decapitated woman in the cathedral.' At first, I didn't believe him, but he repeated it. I went to the cathedral and saw the police in the city, and I called them. They came fast.

"I went back to [the restaurant] and pulled the safety grille down."

He added: "The person who entered [the restaurant] was someone who was very shocked when he was in the cathedral." He just said, 'Sir, in the cathedral there is a beheaded woman.' That's all. I felt shocked. I am still trembling.

The police locked down the city center immediately.

According to the police, the attacker did not carry identity papers that had taken fingerprints to determine whether he was known to security services.

In order to establish the attacker's movements beforehand, they are also examining CCTV recordings. Nice is one of the few cities in France that has an extensive CCTV network.

David-Olivier Reverdy, of the French police union Alliance Police Nationale, said that over the past few days, security forces had warned of an "increased terrorist threat" but that it was impossible to have officers everywhere to avoid attacks.

"We should recognize that municipal and national police officers were quickly on the scene and were able to neutralize the person before he could cause any further injuries or deaths," said Reverdy.

The Conseil Français du Culte Musulman (French Muslim Council, CFCM) condemned the attack on Thursday and called on Muslims to cancel their Mawlid celebrations as a "sign of mourning and solidarity with the victims and their loved ones" from 28-29 October to mark the Prophet's birth.

Estrosi said that the whole of Nice was deeply shocked: "Islamic-fascist barbarism chose to attack inside a church this time before it was a school teacher. It is very symbolic again", Estrosi added.

President Macron is on his way to Nice.

Also on Thursday, in Jeddah, Saudi Arabia, a Saudi man was arrested after injuring a guard with a "sharp tool" at the French consulate, state television reported.

"This attack against a diplomatic outpost, which nothing could justify, is strongly condemned by the French embassy," the embassy declared in a statement, calling it a knife attack. The wounded guard was transported to the hospital. His life is not under threat.

The Avignon shooting occurred in the district of Montfavet. There were no pedestrians injured. The police say they yelled at the man to drop his gun, and then they fired a rubber bullet at him. After he threatened officers, they shot him with live ammunition, a police spokesman said. There is no confirmation of the treatment of this as a terrorist attack.

The attack in Nice on Thursday was a grim reminder of the July 2016 killing of Father Jacques Hamel in his Normandy church. Two men with knives, who had also taken two nuns and two worshippers hostage, cut the 85-year-old priest's throat.

A terrorist drove a 19-tonne truck into crowds celebrating Bastille Day on the famous Promenade des Anglais in Nice in July 2016, killing 86 people and injuring 458 others. Police shot and killed the driver, Mohamed Lahouaiej-Bouhlel, a Tunisian living in France.

Macron said France was engaged in an "existential" battle against Islamist fundamentalism after the murder of Paty at Conflans-Sainte-Honorine on 16 October.

His remarks and his support for the publication by the satirical newspaper Charlie Hebdo of controversial caricatures of Muhammad have sparked angry protests throughout the Muslim world, burning images of the president and calling for a boycott of French goods.

On Thursday, after a minute of silence, Prime Minister Jean Castex left the National Assembly urgently and joined the Interior Minister, Gérald Darmanin, in the ministry's "crisis cell."

Castex told the National Assembly that he had raised the level of security in the country.

"Three of our countrymen were murdered in abject circumstances by a man with a knife. The entire nation is grieved by this cowardly and barbaric act, ” Castex said.

"As Castex added, there was applause:" I wish to salute the intervention of our internal security forces, the national police, the RAID and, in particular, the municipal police, who neutralized the attacker rapidly.

The response of the government is going to be firm, implacable, and immediate. I decided to upgrade the level of security to signal an immediate terrorist threat throughout the country.