There are at least 80 people dead after a truck rammed into a crowd watching Bastille Day fireworks in Nice on Thursday night.

The Paris prosecutor’s office has opened a terrorism investigation over the attack.

The mayor of the southern city Christian Estrosi said on Twitter that it was the worst disaster in the history of Nice.

More than 50 others were injured in the incident.

A government official said the driver of the truck also fired on the crowd before he was killed by police. Sebastian Humbert described it as a clear criminal attack, although the driver was not yet identified.

Mr Estrosi said the truck involved in the incident was loaded with arms and grenades. He had earlier advised locals to “stay in your homes for now” after the attack.

Eyewitnesses said the the truck continued driving through the crowd of people at speed for several hundred metres.

One witness has said he saw the driver emerge from the vehicle shooting and killing many as they left the fireworks display, which thousands had gathered to watch, including a large number of families.

The incident comes eight months after Islamic State militants killed 130 people in Paris, the most deadly of a number of attacks in France and Belgium in the past two years. On Sunday, France had breathed a sigh of relief as the month-long Euro 2016 football tournament ended without a feared attack taking place.

‘Scene of horror’

Regional chief Eric Ciotti told France Info radio from the scene that it was a “scene of horror”. He said the truck had sped along the pavement fronting the Mediterranean, before being stopped by police after “mowing down several hundred people”.

Nice prosecutor Jean-Michel Prette said bodies were strewn about along the roadway. Interior ministry spokesman Pierre-Henry Brandet told BFM TV: “It’s going to be a very high toll.”

Mr Brandet also said: “I can’t give you information on the man’s motives yet”.

Wassim Bouhlel, a Nice native who spoke near Nice’s Promenade du Paillon, said he saw a lorry drive into the crowd and the man then emerged with a gun and started shooting. “There was carnage on the road,” Mr Bouhlel said. “Bodies everywhere.”

One woman told France Info she and others had fled from the vehicle in terror: “The lorry came zig-zagging along the street. We ran into a hotel and hid in the toilets with lots of people.”

“People are running. It is panic. He drove up on the Promenade and ran over everyone,” Damien Allemand, a journalist from Nice Matin told the Agence France Presse (AFP). “There are a lot of people bleeding, probably lots of wounded.”

Mr Allemand said a white truck drove up on to the pavement and into the crowd. Gunfire broke out, though it was not immediately clear whether the shooting was done by police or accomplices of the truck driver. The prefecture of the Alpes-Maritimes department said it was a terrorist attack.

“We saw people hit and bits of debris flying around,” an AFP said, adding that the incident took place near the Hotel Negresco. Terrified pedestrians screamed as they fled the area. “It was absolute chaos,” he said.

The attack occurred around 11pm. Within 20 minutes, a security area had been cordoned off around the Place Masséna.

“We are dealing with a large-scale event,” Mr Humbert said. “All government services have been mobilised.”

The emergency department at the Hôpital Saint Roch was overwhelmed.

‘Condolences’

Minister for Foreign Affairs Charlie Flanagan said he deplored the “loss of life, and offer heartfelt condolences to the people of France from the people of Ireland”.

“This attack on people as they celebrated Bastille Day with friends and family on a fine summer’s evening is particularly horrendous, and my thoughts and sympathies are with the relatives of the dead and injured,” Mr Flanagan said in a statement.

He said his department was monitoring the situation and that the Irish Embassy in Paris was on stand-by to offer assistance to any Irish people affected.

Irish citizens in Nice can contact the Embassy can do so at 0144176700, and “are advised to exercise caution and follow instructions of local authorities”. Concerned families in Ireland are advised to contact (01) 408 2000.

US president Barack Obama said he condemned “what appears to be a horrific terrorist attack” in France.

He offered any help France may need to investigate the attack.

French president Francois Hollande, who was in the south of France at the time, had hours earlier said a state of emergency put in place after the Paris attacks in November would not be extended when it was due to expire on July 26th.

“We can’t extend the state of emergency indefinitely, it would make no sense. That would mean we’re no longer a republic with the rule of law applied in all circumstances,” Mr Hollande told journalists in a traditional Bastille Day interview.

He is tonight heading to the French interior ministry’s crisis centre to monitor and work on a response to the events in Nice.

His interior minister Bernard Cazeneuve is en route to the city.

US Republican presidential candidate Donald Trump postponed a news conference scheduled for Friday in New York to announce his running mate because of the deadly attack.

Additional reporting: Agencies