One person was killed and at least 37 injured after a car mounted the pavement and ran into pedestrians on Las Vegas Boulevard around 6pm local time.
The 1996 Oldsmobile then drove back into the street and mounted the pavement again at a different spot of the boulevard, hitting others.
Six people remain in a critical condition.
Police have confirmed a woman was driving and a three-year-old child was in the vehicle at the time. The toddler was not hurt.
Officers are still investigating whether the driver’s actions were intentional or accidental.
“We will comb through that footage to get a detailed idea of what occurred,” said Las Vegas Police Captain Brett Zimmerman.
“Right now from what we know, we’re looking at it possibly being intentional.”
A counter-terrorism unit was called to the scene, but police later confirmed it was not an act of terrorism.
The woman – who was not injured – was taken into custody and is now being interviewed and tested for alcohol and drugs.
“This is a huge tragedy that has happened on our Strip,” Las Vegas Police Captain Peter Boffelli said.
The crash happened as the final of the Miss Universe pageant was being held at the Planet Hollywood nearby.
Crystal Orren, who was staying near Planet Hollywood, told Sky News: “It was chilling because when it happened [my husband Mike] was inside the hotel room and I was out on the balcony and I didn’t hear anything at all – there was no squeal of brakes and no sound of impact. It was just screaming and then the sirens.”