Twenty people are dead following a horrific wedding limousine crash in upstate New York tourist spot on Saturday.

A person with knowledge of the investigation told the Associated Press that 18 of the victims were in the limo and two were bystanders. The person was not authorised to discuss the preliminary information publicly and spoke yesterday on the condition of anonymity.

Local officials told the Times Union of Albany that a limo speeding down a hill hit bystanders on Saturday afternoon at the Apple Barrel Country Store in Schoharie, about 270 kilometres north of New York City.

State police confirmed Sunday the death toll and said the crash involved two vehicles.

The store is a popular stop for tourists on fall foliage trips.

Customers in the parking lot were killed when they were hit by the limo coming down a hill on state Route 30 at "probably over 60mph," the store manager, Jessica Kirby, told the New York Times.

In a Facebook post on Saturday, the store thanked emergency responders for their actions. The store posted Sunday that it was open "and could use your hugs".

Witnesses described chaos, with a massive turnout of ambulances and other responders.

Bridey Finnegan, who lived near the crash site, said she heard a 'loud bang' when the two vehicles collided in front of Apple Barrel, a store popular with tourists.

"I heard a loud bang, I came out my front door to see what was going on," she told WTEN.

"I saw a lot of people here at the Apple Barrel out in the parking lot. Then I heard screaming.

"Then I saw this large van, a very unusual looking vehicle out here in Schoharie in the bushes and really wrecked, hit a tree."

Finnegan said she watched as first responders broke windows to try and rescue people inside.

The Schoharie County Sheriff's Office, New York State Police, and emergency crews from the Red Cross all responded to the scene.

Here’s a closer look at the scene. This is right by the Apple Barrell Country store. pic.twitter.com/7XJeoOTVIz

— Steve Maugeri (@CBS6SteveM) October 7, 2018

Six ambulances, three fire companies, and two helicopters were at the accident site, according to the Albany Times Union.

Witnesses also saw people running out of the Apple Barrel cafe to try and help after the accident.

Authorities didn't release names of victims or other specifics, but state police set up a hotline for family members. The National Transportation Safety Board is investigating.

The crash occurred during the city's 'Old Stone Fort' weekend, which residents said is the biggest tourism day of the year for the small town.

- AP, with Daily Mail