This is the horrifying moment a lorry mows down a crowd of terrified pedestrians watching fireworks after a heroic motorcyclist flings himself onto the vehicle to try and stop the terrorist attack in Nice.

Footage from two different angles shows the truck ploughing into scores of revellers at roughly 40mph on Nice’s Promenade du Paillon, killing at least 77 people and injuring 50.

In one video, a motorcyclist is seen desperately trying to stop the lorry before as it speeds up approaching thousands of people out celebrating Bastille Day in the port city.

The footage, shot from a nearby balcony, shows the motorcyclist speeding alongside the truck before jumping off the moving bike and running alongside.

He then jumps onto the side, desperately clinging to the canvas, despite having no clue if the terrorist has rigged the truck with explosives – something ISIS are known for doing in the past.

A cache of weapons including hand grenades was later discovered inside the truck.

The motorcyclist then continues to cling to the vehicle as other officers ahead of the vehicle shoot at its front in an attempt to stop the driver, a French Tunisian national who was eventually killed.

It is not clear whether the lorry has already ran over some of its victims, but the balcony footage clearly shows the authorities rushing out to stop and shoot the driver.

Police officers are also seen running out of their car to fire at the terrorist before he reaches the crowd outside during the French national holiday.

In another clip posted to YouTube the lorry is seen from the side colliding with revellers. It reportedly travelled down the promenade for over a mile.

Both clips were posted to YouTube by Pray for France soon after the attack.

After the side-on video captures the lorry careering along the promenade it shows a crowd of hundreds fleeing for their lives in scenes of chaos.

It shows terrified people, including the camerawoman, race inside nearby buildings for cover.

Screams of ‘run’ can be heard and shouts in various languages as people scamper up stairwells and through corridors to escape the scene.

The latest reports state that after driving a mile down the promenade, the driver jumped out of the truck and started to open fire on members of the public.

Officials said the driver was eventually shot dead near the scene. A second suspect is currently on the run, according to French authorities.

Unconfirmed reports in the French media say that ISIS has claimed responsibility for the attack.

Anti-terror police swooped in as the city was put on lockdown and residents were warned to stay indoors.

Guns and grenades were later said to have been found inside the truck, which mounted the pavement at approximately 40mph and steered directly towards hundreds of people watching a fireworks display.