Footage from the scene shows armed police running up the steps and entering the church as emergency services can be heard racing to the scene where three people were killed
A clip from the scene shows armed police running up the steps and entering the church as emergency services can be heard racing to the scene.
The alleged perpetrator screamed “Allahu Akbar” as he was arrested and taken to hospital.
Police also shot dead a gunman in the French city of Avignon two hours later as the country was placed on high alert
In Saudi Arabia, a guard at the French consulate has also been stabbed “with a sharp tool”, official media said.
The attacker was arrested after stabbing and injuring the guard in Jeddah, according to the official Saudi Press Agency.
Mayor of Nice, Christian Estrosi, says he believes the incident is a terror attack – a major police operation is underway in the city and the suspect has been arrested.
He said: “I am on site with the [police] who arrested the perpetrator of the attack.
“I confirm that everything suggests a terrorist attack in the Basilica of Notre-Dame de Nice.”
He added in a follow up tweet: “Nice has paid too heavy a price in the same way as our country in recent years. I call for the unity of the Niçois.”
France’s National Anti-Terrorism Prosecutor’s Office has also launched an investigation into knife attack. President Emanuel Macron also confirmed he is on his way to the city.
The nationalist French politician Marine Le Pen also spoke of a decapitation having occurred in the attack.
The Paris mayor, Anne Hildalgo, also tweeted in support of her counterpart in Nice.
She said: “Attack at the Basilica of Nice: my first thoughts are with the victims and their loved ones affected by this horrible attack.
The Vatican has also condemned the attack, saying terrorism is never acceptable and the Pope is praying for all victims.
Pictures from the scene show the area around the church almost completely empty as armed police set up a major cordon.
Residents in the area have been told to stay inside as police deal with the incidient.
A witness called David, who runs the Brioche Chaude restaurant, opposite the church, told BFMTV he had alerted the police.
“I was selling croissants when a man came in and said to me: ‘Monsieur, there’s a decapitated woman in the cathedral’. I didn’t believe him at first but he repeated it. I went to the cathedral and saw the municipal police and called to them. They came quickly.
“I went back [to the restaurant] and pulled down the security grill.”
He added: “The person who came in [to the restaurant] was someone who had been in the cathedral who was very shocked. He just said: ‘Monsieur there is a woman decapitated in the cathedral’. That’s all. I was shocked. I’m still shaking.”
The Notre Dame Basilica is a Roman Catholic church and is the largest place of worship in Nice.
The French parliament suspended a debate on new virus restrictions and held a moment of silence for the victims.
The attack comes while France is still reeling from the beheading earlier this month of French middle school teacher Samuel Paty by a man of Chechen origin.