ISIS claims responsibility for Nice attack but French investigators still have not found any militant links

"The person who carried out the operation in Nice, France, to run down people was one of the soldiers of Islamic State," the news agency Amaq, which supports Islamic State, said via its Telegram account.

"He carried out the operation in response to calls to target nationals of states that are part of the coalition fighting Islamic State," the statement said.

French security officials are still assessing whether the driver of a truck that rammed into people on the Nice seafront was working alone or in a group, although the Paris prosecutor admitted that the attack bore the hallmark of Islamist militants.

It is possible that ISIS did not have any previous knowledge of the attack, which could suggest that the attack was inspired by the actions of the group rather than orchestrated by them - a theory that experts who talked to Business Insider's Pamela Engel raised in the aftermath of the Orlando shooting.

Mohamed Laouaiej Bouhlel, who drove a heavy truck into crowds in the French city of Nice killing at least 84 people, came from the Tunisian town of Msaken which he last visited four years ago, Tunisian security sources said.

Francois Molins, who said Bouhlel's ex-wife was in police custody, added that the man had shot several times at policemen before his vehicle was stopped and he was killed.

Police found one pistol and various fake weapons in the truck's cabin. They later seized a telephone and computer at his home.

The local, 31-year-old, Tunisian-born Frenchman had a record of violence but was unknown to counter-terrorism agencies drove a rented heavy truck for 2 km (1.5 miles) along the palm-fringed Promenade des Anglais seafront, which was closed to traffic and thronged with thousands of revellers watching fireworks.

Some 25 bullet holes spattered the windshield of the truck, standing where it stopped and the driver was shot dead.