Nice attack: 84 killed as truck drives into crowd

At least 84 people have been killed in the French city of Nice after a truck was driven into crowds celebrating Bastille Day, in what President Francois Hollande called an attack of "an undeniable terrorist nature".

Witnesses said the truck travelled for more than a mile down the famous Promenade des Anglais on the sea front, zig-zagging through the crowd and running people over before the driver was shot dead by police.

French media were reporting that the driver was a Tunisian man who lived in France. A state of emergency, in place since November's Paris attacks, has been extended by three months.

"All of France is under the threat of Islamic terrorism," Hollande said, adding that several children were among the dead.