In a speech outlining how France would move forward in the wake of the attacks, President Francois Hollande expressed his condolences to the families of the victims and said that France must remain strong "because we have to set an example of cohesion and unity for the world".
The Tunisian-born 31-year-old delivery man Mohamed Lahouaiej-Bouhlel drove his weapons-laden truck along the promenade in Nice on Thursday night, killing at least 84 people, before being gunned down by police. "We strongly urge USA citizens in Nice to be in direct contact with your family members in the United States and elsewhere to advise them of your safety".
The French Ministry of Health is now reporting that 202 people were admitted to hospitals for injuries sustained in the attack, 52 of which are in critical condition and 25 of which are in intensive care.
Authorities continue to investigate a deadly attack on revelers celebrating Bastille Day in the French city of Nice. Police shot the truck driver dead.
Hollande, flanked by prime minister Manuel Valls and health minister Marisol Touraine, said numerous 84 dead included foreigners as well as children.
USA government agencies have received constant reports of Islamic State threats to attack France and those threats are regarded as current, a US security official said.
The man was a Nice resident, the AP reported. No group has claimed responsibilty for the attack but he may have been inspired by one. Thousands of people had massed there to watch fireworks for France's national day celebrations.
President Obama on Friday ordered flags to be flown at half staff until Tuesday in honor of those killed in the terrorist attack in Nice, France.
Anti-terrorism prosecutor Francois Molins said the Tunisian attacker was "completely unknown" to the intelligence services but that the assault was "exactly in line with" calls from jihadist groups to kill. The attack ended after police killed the armed attacker in a hail of bullets.
Unlike other recent attacks, numerous victims in Nice are children and teenagers.
Several European Union countries tightened border controls after Thursday's terror attack in France in moves that further erode free travel across the bloc which was already curtailed by last year's migration crisis and earlier terrorist atrocities.
"Solidarity at such times is the most valuable thing we have", said German Chancellor Angela Merkel.
Hollande said France would observe three days of national mourning from Saturday, Paris city hall said the Eiffel Tower will be lit in France's national colours on Friday in tribute to the victims.