As much as 70 persons were killed while several were injured after a van rammed into a crowd marking the Bastille Day in the French Riviera resort on Thursday.
Security forces and ambulances raced to the scene of what is now seen as an obvious terror attack.
One eyewitness reported seeing the driver slam the lorry into revellers celebrating Bastille Day on the city’s famous Promenade des Anglais.
He emerged from the vehicle and started shooting, local resident Wassim Bouhlel said.
He told AFP, “There was carnage on the road, dead bodies everywhere.”
The BBC reports that shots were exchanged between the police and the occupants of the lorry.
A journalist with the Nice Matin newspaper reported from the scene that there was “a lot of blood and without doubt many injured”.
An Agence France-Presse reporter said the incident took place as the firework display was ending, adding: “We saw people hit and bits of debris flying around.”
Another image 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.
An AFP reporter described seeing a white van driving at high speed onto the famed Promenade des Anglais as people were leaving after the annual Bastille Day celebration display.
“We saw people hit and bits of debris flying around,” he said, adding that the incident took place near the city’s famed Hotel Negresco.
Terrified pedestrians screamed as they fled the area. “It was absolute chaos,” he said.