The French Interior Ministry has raised the death toll to 84 from the attack on people celebrating Bastille Day in the Riviera city of Nice.
A truck plowed into a sidewalk full of people who had been taking in a fireworks display on the city’s waterfront.
French President Francois Hollande says a state of emergency in place since last November’s deadly attacks in Paris would be extended.
There has been no claim of responsibility for the attack as investigators try to identify the driver of the truck who was shot dead by police.
Prime Minister Justin Trudeau has tweeted Canada’s support for France.
He says Canada’s sympathy is with the victims, and solidarity is with the French people.
US President Barack Obama has condemned what he calls a horrific terrorist attack.
Obama also says America’s thoughts and prayers are with those who lost loved ones.