The attack in Nice marks a horrific end to one of France's most treasured holidays
The truck plowed into the crowd around 10:30 p.m. local time on the Promenade des Anglais seaside walk in the center of town, where people had gathered to watch the fireworks, news outlets reported.
For France, the attack marked a horrific ending to one of its most treasured national holidays. Bastille Day, celebrated each year on July 14, commemorates the 1789 storming of the Bastille fortress in Paris at the start of the French Revolution.
French people mark the holiday with the oldest and largest military parade in Europe, proceeding down the Champs-Élysées in Paris. Smaller parades are held in many garrison towns. At night, fireworks light up the sky in towns across the country.
This year's parade took place under high surveillance, with France still in an official state of emergency following the terrorist attacks that left 130 people dead in Paris in November.
According to France 24, more than 3,000 police officers were enlisted to secure the parade zone. French President François Hollande was in attendance, along with US Secretary of State John Kerry and New Zealand Prime Minister John Key.
No group has claimed responsibility for the attack, although pro-ISIS groups are reportedly celebrating it.
The violence bears some similarities to the November attacks that erupted throughout Paris, in which Islamic State militants detonated bombs and engaged in shootings in crowded areas, including the Bataclan theater, cafes, and restaurants and outside the Stade de France soccer stadium.