UPDATE - At least 77 dead as truck crashes into crowd in France

UPDATES THROUGHOUT

PARIS (AA) – At least 77 victims were killed after a truck ran over crowds in the southern French city of Nice during Bastille Day celebrations Thursday, according to the city’s mayor.

It is "the worst tragedy in the history of Nice”, Mayor Christian Estrosi said.

Police have indicated the possibility of a terrorist attack and asked residents to stay in place.

“Dear Niçois, the driver of a truck seems to have left dozens dead. Stay now in your homes. More info to come,” Estrosi tweeted earlier.

The city’s prosecutor's office confirmed hundreds are injured as counter-terrorism investigators in Paris have taken charge of the investigation.

Initial reports said a white truck drove into crowds for approximately 2 kilometers (1 mile) along the Promenade des Anglais following celebratory fireworks.

Sebastien Humbert, a Nice police spokesperson told French broadcaster BFMTV that the driver was killed and that authorities are currently treating the incident as an attack.

The French daily Le Figaro quoted security sources as saying, “Several weapons, guns and grenades were found inside the truck." It also said 16 people were in critical condition among the dozens injured.

Several Twitter users posted picture of victims lying in the street.

An Iranian journalist, Maryam Violet, visiting Nice for holiday, told the U.K.’s Guardian that she witnessed the attack and many Muslims are among the dead.

“There were so many Muslim people who were victims because I could see they had scarves over their head and some were speaking Arabic. One family lost a mother and in Arabic they were saying she’s a martyr,” she said.

“People were celebrating and it was so peaceful, it was a festivity vibe, it was right after the fireworks that the truck came and ran over people.”

President Francois Hollande is heading to the interior ministry’s crisis center that the government activated following the incident, the French presidency said on its Twitter account.

Interior minister Bernard Cazeneuve is on his way to Nice.

Shortly after news of the tragedy broke, U.S. President Barack Obama condemned the attack “in the strongest terms”, saying Washington stands in “solidarity and partnership” with its oldest ally.

“On this Bastille Day, we are reminded of the extraordinary resilience and democratic values that have made France an inspiration to the entire world,” he said in a statement, “and we know that the character of the French Republic will endure long after this devastating and tragic loss of life.”

The attack came just hours after the French president announced a state of emergency that was declared after deadly terror attacks last year would not be again extended and would come to end July 26.

France has been under a state of emergency and high terror alert since a Daesh-blamed attack last November killed 130 people across Paris.

The state of emergency was extended three times: twice for three months, and the last time, on May 19, for two months to ensure security during the UEFA Euro 2016 football tournament that ended Sunday.

The last extension was also implemented to help tighten security for the Tour de France -- world's biggest road cycling competition -- which ends July 24.