Taoiseach Enda Kenny has confirmed an Irish man has been caught up in the Nice terror attack. It's understood he's in a critical condition in hospital.

84 people, including several children, were killed when a truck ploughed into crowds celebrating Bastille Day in the southern French city.

Police car parked near the scene

Witnesses say the truck zig-zagged along the Promenade des Anglais for more than a mile.

Le témoignage de cette femme qui aurait vu le camion fou dès 22 heures https://t.co/VLkG7cmt6l pic.twitter.com/8T2KgThZoZ — Nice-Matin (@Nice_Matin) July 15, 2016

The driver then reportedly climbed out and started shooting, before being killed by police. He's believed to have been a 31 year old petty criminal of Tunisian descent. Guns and grenades were found inside the truck.

A state of emergency in France that was due to end in 11 days has been extended for 3 months. It had been in place since October's attacks in Paris. French president Francois Hollande has described it as a terrorist attack:

"Once again, horror has hit France. This attack that has all the elements to be called a terrorist attack is once again of an incredible violence, and we have to do everything we can to fight this terrorist plague."

A woman cries asking for her son as she walk near the scene

The Taoiseach says he is deeply shocked and saddened. In a statement issued this morning Enda Kenny says "Once again innocent people have been targeted at an occasion of joy and celebration."

He also says he wishes to express deepest sympathies and solidarity to President Hollande and to all of France on behalf of the government and Irish people.

The Lord Mayor of Dublin, Brendan Carr, said "On behalf of the people of Dublin, I wish to extend my deepest condolences to French President Francois Hollande, the French Ambassador to Ireland, Jean-Pierre Thébault, to the French authorities and the people of Nice and France."

A Book of Condolence will be opened at the Mansion House, Dawson Street on Monday 18th July and Tuesday 19th July from 10 a.m. – 4.00 p.m. to allow Dubliners to express their sympathies and support to the families and friends of those who died in Nice.

"Our thoughts today are especially with all the families, relatives and friends of those who were killed and injured as they celebrated their country’s national holiday", he addded.

Foreign Affairs Minister Charlie Flanagan said "Irish citizens in Nice who need to contact the Embassy can do so at 0144176700, and are advised to exercise caution and follow instructions of local authorities."

"Consular staff in my Department are also on hand to take calls from concerned families here in Ireland and they may be contacted at any time at 01 408 2000."

Forensic officials work on the beach next to the Promenade des Anglais