Four people believed to be linked to man who killed 84 people in Nice are in police custody, French media report. This breaking news story is being updated and more details will be published shortly. Please refresh the page for the fullest version.

Dozens of people have been killed, including children, after a lorry ploughed into a large crowd watching a fireworks display marking the end of the French national holiday for Bastille Day.

The driver also fired shots, before being killed by police. This is what we know so far about what happened.

Who is the attacker?

The driver of the lorry has been identified by officials as Mohamed Lahouaiej Bouhlel, a 31-year-old man of Franco-Tunisian origin.

Paris prosecutor Francois Molins says Bouhlel was divorced with three children. His ex-wife was taken into custody on Friday morning. A flat he lived in near Nice train station was searched by police on Friday morning.

Mr Molins said Bouhlel was “totally unknown” to security services, and the investigation is still investigating whether Bouhlel acted alone.

He is said to have hired the lorry from a rental company in Saint-Laurent-du-Var, a town to the west of Nice, on 11 July, and had been due to return it on 13 July.

Police said Bouhlel was in possession of an automatic pistol, bullets, a fake automatic pistol and two replica assault rifles (a Kalashnikov and an M16), an empty grenade. Also in the lorry with him were a driving licence and a bank card.

Who was the Nice attacker?

Who were the victims?

At least 84 people were killed, including 10 children and teenagers.

In the hours after the attacks, worried relatives posted images on social media of the missing.

Among the dead was Fatima Charrihi, whose son said she was the first to die.

Another victim, according to reports, was the assistant head of the Nice border police, Jean-Marc Leclerc.

An American boy, Brodie Copeland, and his father, Sean, were also killed. They had been on holiday in Nice.

Three people on a school trip from Germany were unaccounted for.

Read more about the victims

Who was behind the attack?

French security officials are still assessing whether the driver of a truck was working alone or in a group.

No group has said it carried out the attack, but officials said it bore the hallmark of a terrorist organisation.

President Hollande said earlier on Friday that it was “an attack whose terrorist nature cannot be denied”.

Mr Molins said the attack was “in line with the constant calls to kill” from militant Islamist groups, and the investigation would be seek to find out whether Bouhlel had ties to Islamist militants.

Anti-terrorist prosecutors in Paris have launched an inquiry for murder and attempted murder as part of an organised terrorist strike.

Earlier this week, France’s DGSI internal security organisation warned of the danger of further attacks from Islamist militants with “booby-trapped vehicles and bombs”.

The so-called Islamic State has targeted France on several occasions since January 2015.