A lorry has ploughed through a crowd during Bastille Day celebrations in the southern French city of Nice
At least 84 people are dead, including 10 children
202 were injured, 52 remain in critical condition, 25 are in intensive care
The driver of the lorry was shot dead by police
He has been identified as Mohamed Lahouaiej Bouhlel, known to police for violence and petty theft
An eyewitness, who refers to himself as AK, talks to BBC News about what he saw from the scene of the attack.
He says he had to push both himself and his wife on to the pavement, because the truck was less than 10m away.
"There was carnage, absolute carnage. We heard gun shots," he adds.
Witness in Nice: 'I saw this truck speeding towards us'
BBC News is in Nice, where at least 84 people have died after a lorry struck a crowd amid Bastille Day celebrations.
Gavin Lee is doing a Facebook live broadcast and is taking your questions. You can ask them in the comments section below - just click here to watch, external.
BBC Monitoring
Turkey is flying its flags at half-mast today in a show of solidarity with France after the Nice attack, Turkish Prime Minister Binali Yildirim has announced, according to Turkish newspaper Hurriyet.
"We share the pain of the French nation due to this terror incident. As the Turkish nation, I once again express that we will be in cooperation with the French government in the fight against terror and we are ready to provide any help and support," Mr Yildirim said.
Turkey is no stranger to terrorist attacks, the most recent being the Istanbul airport attack last month that killed 45 people.
Another update on the injured.
French health officials say 188 patients were taken to hospitals in the Alpes-Maritimes area after the attack.
Of these, 48 are in a state of "absolute urgency", and 25 are in resuscitation.
Image source, AFPUkrainian President Petro Poroshenko lays flowers outside the French embassy in Kiev
Image source, HANNAH MCKAYFlowers and candles have been left outside the French embassy in London
Image source, AFPPeople observe a minute of silence in front of the French Embassy in Berlin
US Secretary of State John Kerry and his Russian counterpart, Sergei Lavrov, have offered their condolences at the French embassy in Moscow over the Nice lorry attack that left at least 84 people dead.
Kerry and Lavrov laid flowers in front of the embassy building and wrote messages in a book of condolences. Earlier, they had held a minute's silence for the victims ahead of talks on the Syria crisis, AFP news agency reports.
The president of the UN Security Council, Koro Bessho, offered the council's "sincere condolences" to the families of the victims and to the government of France.
He said: "The members of the security council reaffirmed that terrorism in all its forms and manifestations constitutes one of the most serious threats to international peace and security.
"The members of the security council reiterated that any acts of terrorism are criminal and unjustifiable, wherever, whenever and by whomsoever committed."
Simon Coates, a solicitor from Leeds, was cycling with his wife on the promenade in Nice when the attack took place. Speaking to the BBC, he described seeing people with horrific injuries.
"I had been separated from my wife in the crowds. She was behind me and I turned round and followed the path the lorry took checking the people killed to see if she was one of them. I had to check every body and they were so disfigured the only reliable way I could check was to look for her bike and her shoes as most people were not recognisable.
"I saw one woman lying on the ground talking to her dead child, as other people desperately did what they could to save their loved ones.
"As the lorry passed by me a young boy of 10 or so just managed to leap to one side and escape by inches. Tragically dozens of those on foot, young and old alike, were not so lucky. Virtually everyone I saw on the promenade was either dead or beyond real help with truly terrible injuries.
"When I caught up with the lorry it was stationary and an armed policeman was pointing a gun at the passenger side; others were taking cover and getting people away as they suspected a bomb.
"I retraced my steps and thank God I found my wife unharmed at home.
"This is all unbelievably tragic and the whole scene was like the worst nightmare imaginable and I'm not sure if I've really woken up. We're both in a state of shock today. Along the promenade today you can see a screen around dead bodies every 20 yards or so and when I saw all those screens it was clear to me just how bad it was."
This picture, tweeted by the official @Elysee twitter account shows President Hollande, Prime Minister Manuel Valls, Interior Minister Bernard Cazeneuve and Health and Social Affairs Minister Marisol Touraine at a briefing with emergency services at an operations centre in Nice a little earlier.
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Speaking after visiting a hospital where victims of the attack are being treated, Mr Hollande said the truck attack had been carried out "to satisfy the cruelty of an individual, maybe a group''.
He warned that France was "facing a struggle which will be long".
Mr Hollande also praised France's security forces, who he said had made sure that they neutralised the killer.
He said they had invested and committed a great deal and answered all demands made of them since 13 November 2015 (the date when gunmen and suicide bombers killed 130 people in a series of attacks in Paris).
"I salute them, and all those involved... the intelligence service, those involved in the identification process."
The World at One
BBC Radio 4
A former French minister has said security in France is dangerously flawed and Europe has been too slow to make changes on borders and intelligence.Pierre Lellouche, who was on the parliamentary commission of inquiry into last year's Paris attacks, told presenter Mark Mardell that France had not yet properly understood it was at war.
French President Francois Holland said people caught up in the attack will carry trauma through their lives because of what they have seen, even if they're not physically injured.
He said all of France should share the emotion and solidarity with the victims and their families and their loved ones.
President Francois Hollande says 50 people injured in the Bastille day attack in Nice are now "between life and death" - in addition to the 84 known to have died.
French President Francois Hollande has described the attack as "despicable".
He said Nice was one of the most beautiful cities in the world and that the attack had taken place on the day of celebration of liberty.
He said 84 people had died and another 50 injured, who he described as being "between life and death".
He said the victims were French as well as foreigners and that there were a number of children among the dead.
Local reports have named the attacker as 31-year-old Mohamed Lahouaiej-Bouhlel.
Mohamed Bouhlal belongs to a family who resides in Msakin near the city of Sousse, a Tunisian security source told BBC Arabic, on condition of anonymity.
Bouhlal’s parents are divorced and they live in France.
Mohamed used to frequently visit Tunisia, the source added, saying the last time was eight months ago, before he went back to France.
The 31-year-old, said to have been married with three children, was not known by the Tunisian authorities to have been involved in any terrorism activities on Tunisian soil.
However, he was known by to the authorities in connection with drugs and alcohol-related offences.
Earlier, the Tunisian government issued a statement condemning the attack "in the strongest possible terms".
"Tunisia stands by France in its fight against terrorism and supports any measure taken by the French government to protect its territory and the security of its citizens and visitors," the statement said.
A German journalist who witnessed the Nice attack has told how he saw a motorcyclist chase after the lorry and try to open the cabin - but the biker fell and ended up under the vehicle's wheels.
"I stood on the balcony, right on the Promenade des Anglais, and saw how people celebrated there, and how suddenly a truck drove through the crowd," Richard Gutjahr, 42, who shot smartphone video footage of the Bastille Day attack, told the AFP news agency.
"Surprisingly, he drove very slowly, not fast, he drove slowly and he was chased by a motorcyclist," said Gutjahr.
"The motorcyclist attempted to overtake the truck and even tried to open the driver's door, but he fell and ended up under the wheels of the truck."
"Then the driver stepped on the accelerator and the truck sped up, accelerated and drove in a zig-zag course into the crowd.
"In the next 15 to 20 seconds there were shots from several guns. I don't know who shot at whom."
After that, "the panicked crowd ran in all directions. Those who could save themselves ran into the hotels, or sought security in the hotel entrances," he said.
"Right afterwards I personally saw 12 dead bodies, and it was already clear there would be more."
Interpol, the world's largest police organisation, will be getting involved in the aftermath investigations, Reuters news agency reports.
The Interpol team includes "experts in disaster victim identification", Reuters said.
People around the world have paid tribute to the victims of the attack in Nice.
Image source, EPAOutside the French Embassy in Rome, a stream of people are signing a book of condolences
Image source, EPAPrayers were held at the French Institute in Phnom Penh
Image source, Getty ImagesA vigil was held at the Alliance Francaise in Bangkok
Image source, PAFlowers have been laid outside the French embassy in London
Dominic Casciani
Home Affairs Correspondent
Can an attack like Nice ever be stopped?
If we want to live in a free and open society, then no security infrastructure can ever remove all the risks.
But there are really effective methods to stop lorry attacks and to protect public spaces. I'm among a small group of journalists fortunate enough to have seen one of the key methods tested, quite literally, to destruction.
For the whole piece from Dominic, click here.