These are the shocking scenes of French police grappling with a second man, moments after shooting dead Nice attacker Mohamed Lahouaiej Bouhlel.

It followed reports that officers were hunting possible accomplices who assisted Bouhlel with his deadly attack.

Christian Estrosi, president of Nice's regional government said some of the city's 1,200 security cameras had pinpointed the moment the attacker boarded the truck 'in the hills of Nice' and were able to retrace his path to the promenade.

He said: 'Attacks aren't prepared alone. Attacks are prepared with accomplices.'

A police officer approaches the suspect warily with his gun drawn moments after stopping the truck

Shortly before this video was shot, another movie captured audio of six shots being fired at the truck

As several officers struggle with the suspect, one officer keeps his weapon trained on the truck's cab

Two police officers appear to drag away a suspect from the scene of the massacre

Bouhlel killed 84 people during a rampage through Nice following a Bastille Day fireworks display.

Several officers are seen grappling with a man at the rear of the truck which drove for more than a mile targeting innocent tourists walking along the popular Promenade des Anglais in the city.

In the immediate aftermath of yesterday's attack, there were conflicting reports about a possible second gunman.

In a video filmed moments after the truck was stopped, several officers can be seen approaching a suspect lying on the road at the rear of the truck with their weapons drawn.

At least one of the officers can be seen grappling with the individual on the roadway before the man is dragged off by two other policemen.

Eyewitnesses reported seeing Bouhlel exchange gunfire with police before his was shot dead.

Police quickly identified the killer Mohamed Lahouaiej Bouhlel after finding identity documents in his truck

Forensic officers spent the day examining the truck in an effort to identify any of Bouhlel's accomplices

The police said today that French Tunisian Mohamed Lahouaiej Bouhlel died in the passenger seat of the truck

It is understood the killer hired the truck three days before the attack and told police earlier that evening that he was delivering ice cream before running down and killing 80 people and injuring a further 50.

In the background of the video, there are screams from survivors and witnesses who are shocked by what they have just seen.

Armed officers warily approach the truck after firing more than 40 rounds at the vehicle in a desperate attempt to stop it during the one-mile rampage.

Police and forensics teams inspect bodies in the French sunshine where more than 80 people were killed

According to French justice minister Jean-Jacques Urvoas said Bouhlel had been convicted of road rage in January.

He said: 'There was an altercation between him and another driver and he hurled a wooden pallet at the man.'

As it was his first conviction, Bouhlel was given a six-month suspended sentence and had to contact police once a week, which he did, Urvoas added.

He had three children but lived separately from his wife who was taken into police custody on Friday, prosecutor Francois Molins said.

A former neighbour in Bouhlel's hometown of Msaken, about 75 miles south of Tunis, he had left for France in 2005, after getting married, and had worked as a driver there.

French Prime Minister Manuel Valls, pictured, said Bouhlel likely had links to radical Islam and extremism

Police riddled the truck's cab with bullets in a desperate attempt to bring the massacre to a halt

Tunisian security sources said Bouhlel had last visited Msaken four years ago. They also said they were not aware of Bouhlel holding radical or Islamist views, saying he had a French residence permit for the past 10 years without obtaining French nationality.

Neighbours in the residential neighbourhood in northern Nice where Bouhlel lived said he had a tense personality and did not mingle with others.

'I would say he was someone who was pleasing to women,' said neighbour Hanan, standing in the lobby of the apartment building where Bouhlel lived.

'But he was frightening. He didn't have a frightening face, but ... a look. He would stare at the children a lot,' he added.

French Prime Minister Manuel Valls said: 'He is a terrorist probably linked to radical Islam one way or another. Yes, it is a terrorist act and we shall see what the links there are with terrorist organisations.'

Valls said he was 'convinced' that France would win the war against terrorism and radical Islam.

He denied there were any security failings in advance of last night's attack.

However, following last night's attack, French leaders have decided to extend the country's eight-month-old state of emergency.

Several officers approached the passenger side of the of the truck moments after it had stopped

Chief prosecutor Francois Molins said police risked their own lives trying to stop the truck as it traveled more than a mile down the promenade.

Molins said Bouhlel's estranged wife was arrested in Nice on Friday, while Bouhlel narrowly avoided being put behind bars months before the attack.

Witnesses said Bouhlel first crashed into crowds near the five-star Hotel Negresco, then rolled slowly down an otherwise empty road chased by police on foot and, possibly, one on a motorcycle.

German tourist Richard Gutjahr filmed the moment when the unidentified motorcyclist sped alongside the truck, hopping a curb to try to grab hold of the driver's door as two police officers on foot nearby fired a single shot each at the driver.

The motorcyclist fell to the ground, coming within inches of being struck by truck tires that partly crushed the motorcycle, but got up and briefly climbed aboard the side of the accelerating truck before jumping off again.

The truck surged through an intersection into screaming crowds, where Gutjahr could hear the final confrontation involving 15 to 20 seconds of gunfire.

Gutjahr said: 'Police were everywhere in town for the day. They clearly saw he was a danger, because that truck should never have been on the road.'

No group has claimed responsibility for the carnage, but French officials called it an undeniable act of terror. The assault on revelers rocked a nation still dealing with the aftermath of two attacks in Paris last year that killed 147 people and were claimed by ISIS.

Flags were lowered to half-staff in Nice, Paris, Brussels and many capitals across Europe.

President Francois Hollande announced a three-month extension to the state of emergency imposed after the deadly November 13 attacks on Paris and the government declared three days of national mourning to begin Saturday.

Valls added: 'Terrorism is a threat that weighs heavily upon France and will continue to weigh for a long time. We are facing a war that terrorism has brought to us. The goal of terrorists is to instill fear and panic. And France is a great country, and a great democracy, that will not allow itself to be destabilised.'

Molins said 52 of the 202 wounded in the attack remained in critical condition Friday night, 25 of them on life support.

Among the dead, officials said, were 10 children as well as three Germans, two Americans, Moroccans and Armenians, and one person each from Russia, Switzerland and Ukraine. Two Scots were listed as missing.

Christian Estrosi, president of Nice's regional government said some of the city's 1,200 security cameras had pinpointed the moment the attacker boarded the truck 'in the hills of Nice' and were able to retrace his path to the promenade.

He said he suspected Bouhlel did not act alone.

He said: 'Attacks aren't prepared alone. Attacks are prepared with accomplices.'

Estrosi told BFM TV that 'the driver fired on the crowd, according to the police who killed him'.