Britain 'stands shoulder to shoulder with France'
Prime Minister Theresa May has said Britain must redouble its efforts to defeat "brutal" terrorist "murderers" in the wake of the Nice attacks.
She said Britain stood "shoulder to shoulder" with France after a lorry was driven into a crowd, killing 84 people and injuring 202 others.
Mrs May said she would speak to president Francois Hollande "and make clear that the United Kingdom stands shoulder to shoulder with France today as we have done so often in the past". "If, as we fear, this was a terrorist attack then we must redouble our efforts to defeat these brutal murderers who want to destroy our way of life," she said.
Downing Street said a "small number" of Britons were injured in Nice.
The Queen and Prince Philip sent their "most sincere condolences" to the families of those who died. They also said they were "deeply shocked and saddened" by the attack. France has declared three days of national mourning following the atrocity, which comes after attacks in November in Paris in which 130 died and in January 2015 that killed 17.
Eyewitnesses said the Nice attacker - reported to be 31-year-old Mohamed Lahouaiej Bouhlel, a man of French-Tunisian origin - swerved from side to side to hit as many people as possible as he drove for a mile along the Promenade des Anglais on the seafront of the city on the French Riviera. Foreign Secretary Boris Johnson, who celebrated Bastille Day with dinner at the French Embassy in London, said: "If this is a terrorist incident, as this appears to be, this represents a continuing threat to us and the whole of Europe and we must meet it together."
Mr Hollande led a wave of condemnation from world leaders, saying: "France has been hit by a tragedy once again. This monstrosity of using a lorry to deliberately kill people, many people, who only came out to celebrate their national day."
He said a military operation was in place that would allow the mobilisation of 10,000 troops, and that police from across the country would be called to assist their colleagues in Nice. The country's borders were being tightened, said the president, as he vowed that France would show "real force and military action in Syria and Iraq".
Police forces in Britain will review security arrangements at major events scheduled to take place over the next week in the wake of the Nice attack.