Colin Srivastava told the BBC he saw several hundred people running towards him looking panic stricken
- 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
- Copyright: Getty Images
Images from Nice have shown the lorry used in the incident strewn with bullet holes.
The hashtag, meaning "open doors", was also used in the aftermath of the Paris attacks in November last year.
The White House has said US President Barack Obama has been briefed on the incident in Nice.
National Security Council spokesman Ned Price tweets:
A spokesperson for the Foreign Office in London has issued a statement saying: "We are in touch with the local authorities and are seeking more information following the incident in Nice. We are standing by to help any British nationals."
The French president is said to be heading to the Interior Ministry's crisis centre in Paris after the attack.
Earlier today, Mr Hollande said that France would not extend the state of emergency imposed after last November's terrorist attacks in Paris beyond 26 July.
The AFP news agency is reporting at least 60 people have been killed in the Nice attack, citing French authorities.
- Copyright: AFP
It remains unclear who was behind the attack but French media have reported local officials saying that the driver of the lorry was shot dead.
Images circulating on Twitter showed a white lorry stopped in the middle of the promenade with damage to its front, and four police officers observing it while taking cover behind a palm tree.
Other images also show clear damage to the lorry, which is said to have deliberately ploughed into the crowd at high speed.
- Copyright: BBC
Images on social media have shown people running through the streets following the attack.
The local prefecture has urged people in the area to remain indoors, calling the incident "an attack". Meanwhile, Nice Mayor Christian Estrosi said "a lorry driver appears to have killed dozens of people".
A lorry has struck a crowd during Bastille Day celebrations in the southern French city of Nice, with reports suggesting many people are dead.
The incident took place in the city’s famous Promenade des Anglais during a firework display, media reports say. One image on Twitter showed about a dozen people lying on the street, some being tended to.