At least 84 people have died, including kids, after a bunch hit marking in the southern French city of Nice.
It occurred on the famed Promenade des Anglais after a firework display. The motorist was shot dead and grenades and firearms were located inside the lorry.
President Francois Hollande said the assault was of a “terrorist nature”.
He offered a state of emergency by three months across France.
France had been following last November’s attacks in Paris in and hundreds were wounded.
The state of emergency was expected to finish on 26.
“France is badly hit,” Mr Hollande said, adding that “we need to do everything we can to fight against” such attacks.
“All of France is under the threat of Islamic terrorism,” he said, adding that “several children” were among those killed.