Investigators are seeking to establish the motives of the Tunisian-born suspect but are also looking for possible accomplices.

An attacker > killed more than 80 people and injured many by ramming a heavy truck at high speed a crowd watching Bastille Day firework in the French Riviera city of Nice late on Thursday, officials said. The attack comes eight months after Islamic State gunmen and > suicide bombers killed 130 people in Paris.

Here is the latest:

8:15 pm: The ex-wife of the man believed to have ploughed a truck into a crowd of revellers in Nice, killing 84 people, was held for questioning on Friday, a police source said.

Investigators are seeking to establish the motives of the suspect, 31-year-old Tunisian-born Mohamed Lahouaiej-Bouhlel, but are also looking for possible accomplices.

8:00 pm: The Eiffel Tower will be lit in France's national colours from Friday in tribute to the victims of the Nice truck attack, Paris city hall said.

"The mayor of Paris, Anne Hidalgo, has decided to illuminate the Eiffel Tower in red, white and blue tonight and during the (three-day) period of national mourning," it said in a statement, adding that the illumination would start each night at 10.30pm

7 pm: French President Francois Hollande says that around 50 people are in a critical condition "between life and death" after the Bastille Day attack in Nice.

"As I speak 84 people are dead, and around 50 are in a critical condition between life and death," he says after visiting a hospital in the French Riviera city.

6.30 pm: French President Francois Hollande says about 50 people between life and death after Nice attack, reports Reuters.

6.10 pm: An Associated Press reporter says the alert at Nice airport has been lifted, with passengers who had been evacuated being allowed back into the terminal to pick up their bags.

The airport’s website showed flights leaving and landing as usual. In a message posted to the site’s home page, the airport said: “Despite the dreadful events that occurred, access to the airport and Air traffic won’t be disrupted.”

5.45 pm: Associated Press reports two French officials as saying that the man who carried out the attack was a Tunisian living in the city. The officials, who could not speak publicly on the investigation, confirmed that the ID found in the truck matched the dead attacker.

They said the man was living legally in France. Tunisia is a former French colony

5.30 pm: Passengers ordered out of Nice airport; military seen inside closed terminal building, reports AP

5.00 pm: The foreign ministries of Armenia, Ukraine and Switzerland are reporting one of their citizens were killed in the attack.

4.05 pm: French President Francois Hollande and Prime Minister Manuel Valls arrive in Nice by plane. The pair posed with Interior Minister Bernard Cazeneuve on the airport tarmac in a show of solidarity.

3.50 pm: Two Americans among the victims, says the U.S. State Department.

3.45 pm: At least two children died and about 50 were hospitalised in the attack, AFP reports.

An hospital official, quoted by AFP, says two children died during surgery at a paediatric hospital close to the scene of the attack and others were "hanging between life and death".

3.15 pm: At least 50 children are hospitalised after the attack, AFP reports.

2.15 am: France declares three-day national mourning.

2.05 pm: The attacker is a 31-year-old Franco-Tunisian, whose identity papers were recovered from the vehicle after the carnage. Police have not yet released the attacker's name, but say he lived in Nice.

1.35 pm: Nice truck attacker formally identified, AFP reports quoting a police source.

1.25 pm: A lawmaker of the region that includes Nice says some people tried to escape the attack by going into the sea.

“A person jumped onto the truck to try to stop it,” Eric Ciotti told Europe 1 radio. “It’s at that moment that the police were able to neutralise this terrorist. I won’t forget the look of this policewoman who intercepted the killer.”

1.05 pm: Russian news agencies quote Irina Tyurina, spokeswoman for the Russian Union of Travel Industry, as saying that a Russian woman was killed and her friend hurt in the attack. According to the agencies, Tyurina said she got the information from insurance agencies. “Two friends from Russia were taking a walk on the Promenade des Anglais. One was killed by the truck, the other lightly injured, she’s got broken toes and some other minor injuries,” Tyurina said.

Thousands of Russian tourists are estimated to be holidaying in Nice.

12.25 pm: French ambassador ‘thanks India for solidarity," reports our correspondent Kallol Bhattacharjee. "India France together against terror".

12.15 pm

I have spoken to our Ambassador in France Shri Mohan Kumar. He has again confirmed that all Indians are safe. >@Indian_Embassy — Sushma Swaraj (@SushmaSwaraj) >July 15, 2016

11.45 am: British Foreign Secretary Boris Johnson says he was shocked and saddened by the attack.

Shocked and saddened by the appalling events in Nice, and the terrible loss of life. — Boris Johnson (@BorisJohnson) >July 15, 2016

11.25 am: France, hit with two waves of attacks in 2015 that killed 147 people, has long known be a top target of Islamic State. In September 2014, its spokesman, Abu Mohammed al-Adnani, referred to “the filthy French” in a statement telling Muslims within the country to attack them in any way they could, including “crush them with your car.”

The message was not limited to France. It addressed “disbelieving Americans or Europeans, especially the spiteful and filthy French or an Australian or a Canadian.”

11 am: The attack in Nice has left 84 dead and 18 in a "critical condition", Interior Ministry spokesman Pierre-Henry Brandet says.

10.45 am: Nice truck attacker was known to French police for common law crimes, but not to intelligence services, Reuters reports, citing a police source.

10.20 am: Here is > what we know about what French President Francois Hollande has declared an "undeniable" terrorist attack.

(People cross the street with their hands up as a soldier secures the area on Friday after dozens were killed along the Promenade des Anglais in Nice, France, when a truck rammed a crowd celebrating the Bastille Day national holiday. Photo: Reuters)

9.50 am: AFP reports: President of the Nice region Christian Estrosi says the truck driver fired from a pistol several times before being shot dead by police.

"At the moment he was shot dead by police, he had fired several times," he says.

A source close to the investigation says an "inactive" grenade was found inside the 19-tonne truck, as well as "several fake rifles".

Regional lawmaker Eric Ciotti describes "terrifying images, a scene of absolute horror, with many children among the dead".

"Families who were sharing a moment of leisure were targeted. It was a symbolic day in a symbolic place. That... motivated the attack," he says.

9.40 am: President Pranab Mukherjee > strongly condemns the attack.

9.35 am: The U.N. Security Council strongly condemns the “barbaric and cowardly terrorist attack”, AFP reports.

9.30 am: Prime Minister Narendra Modi condemns the deadly attack, terming it a “mindless act of violence”. > Read more

9.15 am:

Appalled by the horrific attack in Nice. I strongly condemn such mindless acts of violence. My thoughts are with the families of deceased. — Narendra Modi (@narendramodi) >July 15, 2016

9.10 am: “We have offered any assistance that they may need to investigate this attack and bring those responsible to justice. We stand in solidarity and partnership with France, our oldest ally, as they respond to and recover from this attack," says U.S. President Barack Obama.

9.00 am: Obama strongly condemns the attack, saying it appears to be a “horrific terrorist attack”. > Read more

8.45 am: “Our Ambassador in Paris is in touch with the Indian community in Nice. So far no report of any Indians affected,” External Affairs > Spokesperson Vikas Swarup tweets.

8.30 am: No Indian is reported to be affected. MEA says the Indian Embassy in Paris had opened a helpline number 33—1—40507070.

8.15 am:

At least 30 people so far reported dead after a truck ran into a Bastille Day crowd in Nice >https://t.co/Iq0Io1iNG1 >https://t.co/eWd7Bvyahe — Reuters Top News (@Reuters) >July 14, 2016

8.00 am: “European and Asian leaders pay respect to the victims of Nice attack. We stand united against violence and hatred,” European Council president Donald Tusk tweets. > Read more

7.45 am: > The state of emergency imposed since a previous attack on Paris last November to be extended for another three months, says Hollande.

7.00 am: European Council President Donald Tusk tweets weapons and grenades were found inside the 25-tonne, unmarked truck.

6.30 am: “Tragic paradox that the subject of Nice attack was the people celebrating liberty, equality and fraternity,” he says.

6.30 am: BFM TV says 80 people killed in the attack.

6.00 am: Hollande says the attack was clearly a terrorist assault.

5.45 am: Hollande says at least 77 people were killed in an attack.

5.50 am: Counter-terrorist investigators seeking to identify the driver who, a local government official says opened fire before police shot him dead.

5.30 am: “Neither the place nor the date are coincidental,” a former French intelligence agent and security consultant, Claude Moniquet, tells France-Info.

5.00 am: “The lorry came zig-zagging along the street. We ran into a hotel and hid in the toilets with lots of people,” a woman tells France Info that she and others fled in terror.

4.45 am: Police deny rumours on social media of a subsequent hostage-taking in Nice.

4.30 am: An Interior Ministry spokesman says “several dozen” died. Nice-Matin says 42 people are in critical condition and many others injured.

4.20 am: Local government leader Christian Estrosi put the death toll at 77.

4.10 am: “It's a scene of horror,” a local member of parliament, Eric Ciotti, says the France Info radio. The truck had “mown down several hundred people,” he says.

4.05 am: “I saw people go down,” says bystander Franck Sidoli, who is visibly shocked. Reuters

4.00 am: President Hollande, who raced back to Paris from the south of France after the attack, was due to address a sleepless nation on television at 3:30 a.m. (0130 GMT). Hours earlier, in a traditional Bastille Day interview, he had said an eight-month state of emergency might end in two weeks time.

3.45 am: An AFP reporter describes seeing a white van driving at high speed onto the famed Promenade des Anglais as people were leaving after the annual Bastille Day celebration display. "We saw people hit and bits of debris flying around," he says.

3.40 am: Police and ambulances rush to the scene and authorities from the local Alpes-Maritimes prefecture urge residents to stay indoors.

3.35 am: The truck rams a crowd on the Promenade des Anglais seaside walk in the centre of town, regional newspaper Nice Matin reported, citing its own reporter at the scene.

3.30 am: At least 30 people killed in Nice when a truck rams a crowd celebrating the Bastille Day national holiday, French TV channel BFM TV said.