At least 84 people killed while at least 18 remain in critical condition, according to Nice police
U.S. officials confirm at least two Americans were killed; three Australians injured, according to country's foreign minister, Julie Bishop; two Chinese citizens were also injured, the Chinese consulate in Marseille tells CNN
Identity of assailant was known to authorities for petty crime violations, based on a provisional identification of the attacker. But he was not known to security services for jihadism or Islamist extremism, a source close to the investigation tells CNN
Authorities are working to determine whether an I.D. card of a 31-year-old French-Tunisian found in the truck cab matches the body of the driver, according to a police source reported by AFP
No one has yet claimed responsibility for the attack
Eyewitness: 'It was well-planned'
Eyewitness Andy McArdy works at Le Queenie, a restaurant on the Promenade des Anglais. He tells CNN of his shock that an attack like this has happened in Nice.
"Maybe though something would happen during the Euro 2016, but that passed without incident. Nice was a soft target, a family outing, people enjoying the music, the promenade.
He continued: "It was very well planned; they knew that the noise of fireworks would mask the noise of gunfire, so that people would think that they were hearing fireworks, instead of, sadly, live gunfire that killed people."
Recalling the moment the truck appeared on the promenade, McArdy said: "He must have broken through the barriers ... You could hear the pop, pop, pop. There were bodies everywhere.
"Everyone came rushing in the restaurant -- about 100 people -- trying to find safe passage. They ended up staying in the building until midnight, when police said it was safe to leave.
McArdy says the scene today has "an extremely eerie atmosphere."
"Nothing has been cleaned away -- the bodies have been removed, but the debris and the blood are still there."