Death toll in Nice massacre expected to rise as France again in state of shock and grief

“Bodies were falling like skittles,” said one witness.

Another said: “It was like hallucinating. The lorry zigzagged; you had no idea where it was going. My wife, a metre away, was dead. It ripped through everything; poles, trees. Some people were hanging on the door and tried to stop it."

Among those injured are 52 people said to be in a critical condition with 25 of them are fighting for their lives in intensive care.

The carnage lasted for more than a mile as the killer - named as local delivery man and petty criminal Mohamed Lahouaiej Bouhlel - deliberately targeted people on the seafront, swerving from side to side and said to have been travelling at 50 mph.

As some people ran for cover, others threw themselves into the sea to avoid death and injury. Parents flung their children over fences in a desperate bid to protect them.

When the lorry eventually stopped in a pedestrianised area, Bouhlel was said to have pulled a gun and was shot dead by police. Guns and grenades were later found inside the vehicle.

Mr Hollande, who said the “monstrosity” of using a lorry to kill people on the French Riviera had all the hallmarks of Islamist extremism, declared: “France is in tears; it is hurting. But it is strong and she will be strong, always stronger than the fanatics, who wish to hurt us."

Sylvie Bermann, the French ambassador to the UK, described the massacre in Nice as an attack on the founding principles of the republic: liberty; equality and fraternity.

The president announced a three-month extension to the state of emergency, He said the country’s borders were being strengthened and that 10,000 additional troops were being made available for mobilisation. He also vowed that France would show "real force and military action in Syria and Iraq".

Three days of national mourning have been declared following the atrocity, which comes after co-ordinated terror attacks in November in Paris when 130 people were murdered and in January 2015 in the so-called Charlie Hebdo tragedy, which claimed 17 lives.

France, which just days ago had expressed relief that the European football championships it had hosted had ended without serious incident, is today asking itself why it is being targeted and how its people can be protected. Mr Hollande was reported to have been booed as his convoy of vehicles travelled to southern France.

Last night, a vigil for the dead and injured took place at Nice cathedral.

This morning, the French authorities are trying to piece together the circumstances behind yet another terror attack.

Bouhlel, a 31-year-old father-of-three, estranged from his wife, was described as being of French-Tunisian origin. He was not known to the security services but was known by the police.

The killer was reported as having convictions for theft, domestic violence, and possessing a weapon. He was under judicial supervision and had recently lost his delivery job after falling asleep at the wheel and crashing into several cars.

According to local reports, he was not said to be religious and did not attend a mosque. Neighbours described him as withdrawn and quiet. A cousin of his estranged wife told the Daily Mail Bouhlel drank alcohol and took drugs. “He beat his wife. He was a nasty piece of work,” he said.

Police officers and forensic teams searched the killer’s flat in Nice as well as his former marital home.

He was reported to have hired the lorry on Monday, taking the biggest in the fleet; a 19-tonne vehicle, normally used for removals.

Theresa May, on her first official visit as Prime Minister to Scotland, condemned the "horrifying" terror attack and made clear Britain stood “shoulder to shoulder” with France and its people. She stressed how, in light of the last terror attack, the UK had to redouble its efforts to defeat the "brutal" terrorist murderers.

Earlier, a meeting of Whitehall’s emergency Cobra committee was held with police forces in Scotland, England and Wales told to review security measures at all major public events in the coming days.

Deputy assistant commissioner Neil Basu of the National Police Chiefs' Council, said: "UK policing continues to operate at a heightened state against the backdrop of a severe threat level; that level has been in place since 2014.

"Our policing tactics and security measures are constantly reviewed and we, along with our partners, are working around the clock to keep our cities as safe as can be,” he added.

Abroad, world leaders reacted with horror and sadness to the Nice attack.

US president Barack Obama condemned in the strongest terms the “horrific terrorist attack". German chancellor Angela Merkel said her country stood on the side of France in the fight against terrorism. Canadian Prime Minister Justin Trudeau expressed Canada’s “solidarity with the French people". Pope Francis said he was praying for the victims and asked God to “convert the hearts of the violent blinded by hate".

At home, the Queen sent a message of condolence to Mr Hollande saying: "I was deeply shocked and saddened to hear of the terrible loss of life in Nice.”

David Cameron, the former PM, condemned the "sickening and dreadful attack" and said the terrorists would “never defeat us,” while First Minister Nicola Sturgeon said: "Scotland stands in sadness and solidarity with France.”

The Muslim Association of Britain expressed its condolences to the bereaved and added: "We stand together with the people of France during these difficult times."

Flags on government buildings across the UK were flown at half mast. The Palace of Westminster was last night lit up in the red, white and blue colours of the French tricolour. At the Open golf championship in Troon, players wore black armbands out of respect for the dead.