France Bastille Day attack: The world reacts

A terror attack that targeted revelers celebrating Bastille Day in France left at least 80 dead, according to authorities. A truck filled with weapons and hand grenades slammed into people gathered late Thursday to watch fireworks in the southern French city of Nice.

As the nation mourns, celebrities, political figures and world leaders took to social media to condemn the attack and mourn its victims.

French president Francois Hollade wrote on Twitter that "France is tearful, grieving, but it is strong and will always be stronger than the fanatics who want to attack today."

Belgian Prime Minister Charles Michel also shared his condolences on Twitter.

"All my thoughts are for the victims of the despicable and cowardly Nice attack," he wrote. "Solidarity with France."