The BBC's Andrew Plant, who is in Nice, says police found a wallet in the lorry which led to them obtaining bank cards that subsequently led to the raid on an address.

It is not, at this stage, known what they may have found. 

The lorry is still on the Promenade des Anglais, and bullet holes can be seen in its windscreen. 

Image source, AP

French newspaper Le Figaro reports that 30,000 people were on the Promenade des Anglais in Nice when the attack happened. The area will remain closed until further notice, it quotes the city's town hall as saying.

Eyewitness Imad Dafaaoui was at the scene when the attack took palce. He told the BBC: "It was terrifying. I managed to run away toward the beach, but it was the wrong decision. I had to jump over a fence because otherwise the lorry would have got me.

"We saw dead bodies. After the attack we went back to help people. It was really gore (sic)."

He said it was difficult for the emergency services because there were just too many injuries to deal with, "blood was everywhere," he said.

The French government has provided psychiatrists for witnesses, a reporter from the French newspaper Le Monde has tweeted. 

She says: "Skander, 5-years-old, came to tell psychiatrists at the victims' support centre what he saw.

"'There was the dead people and the sea.' Behind the windows of the car, he saw 'the thing'. A body projected on them (the windows), his mother said."  

The World at One
BBC Radio 4

A hospital in Nice says it has treated some 50 children and adolescents injured in the Bastille Day attack, including two young teenagers who died during or after surgery.  Stephanie Simpson is communications director at The Lenval Foundation children's hospital.  She told the World at One's Mark Mardell that many members of staff knew people who were injured and that emotions were high.     

Image source, Reuters

UN Secretary-General Ban Ki-moon has condemned the attack in Nice, calling for intensified efforts to confront terrorism and violent extremism. 

In a statement, external, he said he "stands firmly behind the French government and people as they confront this threat and stresses the need to intensify regional and international efforts to combat terrorism and violent extremism." 

If you are just joining us, here is a recap of what we know of Thursday's attack in Nice during Bastille Day celebrations:

• At least 84 have died, including many children, when a driver slammed a lorry through a crowd
• The attacker was shot dead by police. He has not been officially identified, but identity papers found in the truck are those of a 31-year-old French-Tunisian, reports say
• He has been named by local media as Mohamed Lahouaiej-Bouhlel  
• President Francois Hollande says the attack is of "an undeniable terrorist nature"
• No group has claimed responsibility
• Here is our story with the latest developments
• We have some witness accounts here
• Watch footage of police shooting attacker

French officials have conducted searches on the flat of the man suspected of carrying out the attack in Nice, as AFP correspondent Catherine Marciano tweets.

Police have not identified the man, but he has been named by local media as Mohamed Lahouaiej-Bouhlel.

BBC Monitoring

The daily radio bulletin for so-called Islamic State has made no mention of the attack in Nice.

The terror group's Al-Bayan radio has been used in the past to claim credit for some attacks in the West, although its self-styled "news agency" Amaq is more commonly the first to report claims. 

Al-Bayan's failure to mention the attack should not be taken as an indication that a claim from the group is less likely, the BBC's Monitoring team said. 

Amaq itself has not issued any reports since 20:52 BST on 14 July, before the attack took place.  

Image source, AFP

Details are still emerging about the identities of the victims but here is what we know so far:

• One French: a 60-year-old man
• Two Americans: a 51-year-old dad and his 11-year-old son
• One Swiss: a 54-year-old woman
• One Russian
• Two Armenians

Read more about the victims here

France's BFMTV reports, citing police sources and locals, that the attacker was married and had three children. He was not very religious, it says.

 BMTV has also tweeted, external that he "did not fully observe Ramadan this year, according to his neighbours".  

To read more from the broadcaster, click here, external. 

Image source, A

Several eyewitnesses have been describing the horror of the attack in Nice and its aftermath. 

Damien Allemand, a journalist with the local newspaper Nice Matin, was at the waterfront after the fireworks had finished.

"A fraction of a second later, an enormous white truck came along at a crazy speed, turning the wheel to mow down the maximum number of people," he said.

"I saw bodies flying like bowling pins along its route. Heard noises, cries that I will never forget."

Click here for more.

There has been a 45-minute Cobra meeting this morning chaired by deputy security adviser Paddy McGuinness.

Following that meeting, some details have emerged via a Downing Street spokesman: 

• A consular team of eight from the British Embassy was deployed overnight, with four more sent this morning
• The British Ambassador, Sir Julian King, has now arrived in Nice
• The British government is "aware of a small number of British nationals who are injured". This is a greater number than the one Briton injured that Foreign Secretary Boris Johnson referred to earlier, but the prime minister's spokesman would not offer further details
• The meeting discussed the threat in the UK: the threat level remains at severe
• Police are looking at the situation and reviewing security at big public events over the next week
• Downing Street said this was the "prudent" thing to do in the circumstances

The intelligence services were at the meeting, as well as the Metropolitan Police, the MoD, the Home Office, the Department for Transport, the Foreign Office, plus staff from the British Embassy in Paris.

The national security adviser was there, too.  

Nathalie was on the promenade in Nice with her husband when the attacker drove the lorry into the crowd. She took shelter in a restaurant nearby. 

Speaking to the BBC she described a horrific scene: 

"I stayed one hour with two women holding their hands; one was having her leg... Well, the truck drove on it... it was horrible. 

"The other women was bleeding [like] crazy. There was one dead guy with... We put a tablecloth of the restaurant over him. There were two children... there were about ten people, one dead and eight, nine people injured around us."

Image source, AP

• June 2016 - man claiming allegiance to so-called Islamic State kills two police officials in Magnanville, near Paris 
• November 2015 - multiple attacks on Paris by seven gunmen and suicide bombers kill 130 people and injure more than 350 in the deadliest terror attack in French history 
• June 2015 - man with suspected links to Islamist radicals decapitates his boss after ramming his car into an area containing flammable liquids at a factory in Lyon 
• January 2015 - three days of attacks by gunmen in Paris leave 17 people dead, starting with an attack on the office of satirical magazine Charlie Hebdo and ending in two sieges 
• March 2012 - a gunman kills seven in Toulouse and Montauban, including a teacher and three children at a Jewish school