French National Front leader Marine Le Pen has said on the party's website, external that "the war against Islamist fundamentalism" must begin.

Meanwhile, former French President Nicolas Sarkozy has said on Facebook, external that:  "We are in a war that will last, with a threat that is constantly renewing itself. 

"Adapting and continuously strengthening our plan of action against Islamist terrorism remains a top priority. 

"Exceptional firmness and vigilance is needed in every moment as well as over a long period of time. Nothing can be as before."

Image source, AP

Police are yet to formally confirm the identity of the man behind the wheel of the white, articulated lorry that ploughed into hundreds of people celebrating Bastille Day on the seafront in Nice.

But details are emerging of a 31-year-old man, known to police, but not previously linked to jihadist groups.

As emergency services tended to the men, women and children left dying and wounded on the Promenade des Anglais, police scoured the lorry for evidence.

Inside the vehicle they found papers that apparently identified him as a Franco-Tunisian or a man of Tunisian origin who lived in Nice.

For more, click here. 

French Prime Minister Manuel Valls is now talking about the Nice attack. 

He says terrorism is a threat that is "weighing heavily on France". 

Mr Valls said: "The goal of terrorists is to instill fear and panic. 

"But France is a great country and a great democracy that will not allow itself to be destabilised." 

He adds that there will be three days of national mourning starting tomorrow. 

A man walks through debris scattered on the street the day after the Nice attack. 

Image source, Reuters

AFP

Image source, ALL Sport/Getty Images

The Tour de France time-trial stage is to go ahead, Agence France-Presse is reporting.   

Defending champion Chris Froome is currently in the lead of the cycling race.    

Christian Estrosi, the former mayor of Nice, has told local media in France that about 10 children were killed in the Nice attack. 

Associated Press reported him as saying that France needed to think carefully about its next response to attacks, as previous responses had not been enough to protect the people.   

Frank Gardner
BBC Security Correspondent

This is not the first time in recent years that someone has deliberately driven a truck into pedestrians on a French street. 

But the scale, speed and death toll from this apparent attack in Nice are unprecedented. 

It follows a call by so-called Islamic State (IS) spokesman Abu Muhammad Al-Adnani some months ago for IS followers to do exactly what this truck driver did. 

This, and other calls for attacks in Europe, are partly in response to the significant losses being experienced by IS to the shrinking territory it controls in Syria and Iraq. 

US-led airstrikes, including by French warplanes, are taking a particularly heavy toll there. 

At home, France has become the number one target of opportunity for IS and its supporters, unperturbed by the national state of emergency that has just been extended.

According to French newspaper Nice-Matin, 54 children have been admitted to the Lenval hospital in Nice since Thursday evening. 

Several children are reported to be among those killed in the attack. 

Image source, AFP/Getty Images

If you are just joining our live coverage of the Nice attack, here is what we know so far:

• 84 people have been killed, and about 50 injured, after a lorry drove into a crowd of people celebrating Bastille Day on Thursday
• The driver ploughed on for 2km (1.4 miles) along on the Promenade des Anglais at about 23:00 local time, before being shot dead by police
• The driver opened fire on people in the crowd, according to local reports. Police fired back and the driver was eventually shot dead
• The driver has been identified locally as a 31-year-old man of Franco-Tunisian origin from identity papers found inside the lorry. However, police are yet to confirm the details
• Police found guns and a grenade inside the lorry, but later said these were fake. It was not initially clear if he was acting alone
•  In the area around Nice, the anti-terror alert has been raised to its highest level
• President Francois Hollande was flown back to Paris from a visit to Avignon, joining Prime Minister Manuel Valls in a crisis room

• President Hollande said it was "an attack whose terrorist nature cannot be denied"
• Only hours before the Nice attack, President Hollande had announced that France's state of emergency would be removed later this month. He has since announced it will be extended

More from Nader El Shafei, who describes looking the attacker in the face moments before he was shot dead by police.

Egyptian Nadar el Shafei has described how he tried to speak to the truck driver during the attack, not realising his intentions. 

He told the BBC: 

The city of Marseille, which is around 120 miles from Nice, has announced it is cancelling a fireworks show planned to take place on Friday evening.

While the identity of the attacker is not yet clear, it is "quite likely" that the person has a connection to the local area, which has a long history of jihadist radicalisation, says terrorism expert Peter Neumann.

Professor Neumann, from King's College London, says dozens of people from Nice have joined so-called Islamic State and he describes the area as a ‘jihadist breeding ground’.

Here is the scene of the attack in Nice at the moment, which remains cordoned off. 

BBC Monitoring

French newspapers are struggling to come to terms with last night's events in Nice, with many front pages carrying an image of the bullet-ridden truck on their front pages. 

La Depeche du Midi reports "carnage on the Promenade des Anglais" while Paris Match describes an "apocalyptic scene" and calls Nice "a ghost town" since the incident ended.

"Nice: The horror and the panic" is the front page headline of La Depeche. 

La Figaro speaks of "a new horror".

The incident is also headline news in Russia and the Middle East. 

Al-Jazeera Arabic dedicated its entire morning bulletin to coverage of the attack.

Image source, EPA

World leaders have joined the outpouring of sympathy for the victims of the Nice attacks.

European Council president Donald Tusk, at the Asia-Europe Meeting in Mongolia, called it "a sad day for France, for Europe", and was one of many to point out that the attack hit on the day France was celebrating freedom, equality and brotherhood.

Read more here.