It was eventually stopped when police shot dead the driver.
Meanwhile, French security chiefs began a meeting in Paris as Nice's seaside boulevard reopened to traffic on Saturday.
"We are now facing individuals who are responding positively to the messages issued by the Islamic State without having had any special training and without having access to weapons that allow them to commit mass murder", Cazeneuve said, according to the Post.
Bernard Cazeneuve, the French interior minister said the killer "appears to have become radicalised very quickly". while a neighbour of his ex-wife added: "Mohamed only started visiting a mosque in April". A series of attacks in recent years have shown that radical jihadi networks are seemingly able to obtain guns, and even heavier automatic weapons, easily in France.
"Investigators still have not discovered a direct link between Islamic State and the attacker, so it is a cheap claim".
"Ibrahim Bouhlel, a nephew, said his uncle had never had money problems, and had told relatives this week that he was planning a trip back to Tunisia for a family party".
An attacker drove a truck into a crowd of people celebrating Bastille Day in Nice, France, on Thursday night.
President Francois Hollande said the country would observe three days of mourning as he warned the death toll could rise further, with more than 50 people still fighting for their lives.
"France was struck on the day of its national holiday, July 14, the symbol of liberty", Hollande said.
Update 11.30am: An Irish man believed to have been injured in Thursday's terrorist attack in Nice has been located safe and well.
The attack plunged France into new grief and fear just eight months after gunmen killed 130 people in Paris.
Lenval spokeswoman Stephanie Simpson said that "five children are still in critical condition and one child has stabilised", adding the hospital had treated 30 children the night of the attack.
No group has claimed responsibility for the attack yet, including Islamic State. But neighbors in the Nice neighborhood where the Bouhlel used to live told The Associated Press his estranged wife had been taken away by police on Friday.
Residents of Nice and foreign tourists were killed, among them four French citizens, three Algerians, a teacher and two schoolchildren from Germany, three Tunisians, two Swiss, two Americans, a Ukrainian, an Armenian and a Russian.