Image copyright Family handout/ CBS Image caption Erin and Shane McGowan (L) and Amy and Axel Steenburg (R) were married in June

A limousine that crashed and killed 20 people had failed an inspection and should not have been on the road, New York Governor Andrew Cuomo says.

Mr Cuomo also told a news conference that the driver did not have the appropriate licence for it.

Two newlywed couples and four sisters - ranging in age from 30 to 35 - are among the 20 people who died in Saturday's collision in New York state.

Officials say the crash is the worst US road tragedy in nearly a decade.

Mr Cuomo told reporters the vehicle failed a state vehicle inspection last month and the driver did not have the correct permit to operate a limo with passengers.

He added, however, that officials did not yet know the cause of the accident - whether it was an issue with the vehicle or a driver error.

The governor said New York would request a cease-and-desist order from the courts to prevent the company, Prestige Limo, from operating until the investigation was completed.

How did the crash occur?

The crash occurred near the town of Schoharie in New York state on Saturday afternoon.

According to witnesses, the white SUV-style limo failed to halt at a stop sign, and was travelling at around 60mph (95km/h) when it flew through an intersection, hit an empty car outside the Apple Barrel Country Store & Cafe, and then hurtled across a drainage ditch.

All 18 people on board, as well as two pedestrians, were killed outside the restaurant, which is popular among tourists who come to see the trees change colour in the autumn.

Officials say it is the deadliest crash since the 2009 when Colgan Air Flight 3407 crashed near Buffalo, New York, killing 50 people.

One victim's relative said the hired limo was a replacement for "some kind of bus" that was supposed to take the group on a tour of wineries and breweries for Amy's 30th birthday party.

The family member told the Washington Post one of the victims sent a text before the crash, saying the limo "appeared in terrible condition".

Who are the victims?

Amy and Axel Steenburg wed in June and were celebrating Amy's birthday when their driver lost control of the vehicle in upstate New York.

Erin and Shane McGowan - who also married in June - died, too, in the tragic accident, say relatives.

Image copyright Family handout Image caption From left: Allison King, Abby Jackson, Mary Dyson and Amy Steenburg

Tom King, 35, said his four sisters who died - Abigail Jackson, Mary Dyson, Allison King and Amy Steenburg - "were very tight".

"They were the Four Musketeers," he said, outside their parents home in Amsterdam, New York.

Media playback is unsupported on your device Media caption The cause of the crash is unclear

"They were beautiful girls, full of life. They had their whole lives ahead of them," aunt Barbara Douglas said describing the four sisters.

"One just got married and that's what this was: her new husband was giving her a surprise birthday party," she told the New York Post.

'I love you more than words can say!'

In Mrs Steenburg's last ever Facebook post, dated on 3 October, she thanked her husband for "being so kind and loving".

"I just wanted to say Axel Steenburg I love you more than words can say!" read the post.

Axel's brother, Rich Steenburg, was also killed in the crash. According to an online fundraiser to cover his funeral expenses, he has one young daughter.

Other victims include Robert and Mary Dyson, who were married in 2009 and have one son together.

Matthew Coons, who served as a groomsman at the Steenburgs' wedding, was also killed, along with his girlfriend Savannah Bursese.

Patrick Cushing, and his girlfriend of two years, Amanda Halse, have also been confirmed as among the dead.

An online fundraiser for the children of Abigail and Adam Jackson, who were left orphaned by the crash, has raised over $57,000 (£43,000) as of Monday.

"Adam and Abby were amazing parents to these girls and taken much too soon," the page says, adding that the children are both under five years old.

Valerie Abeling told CNN that her niece, Erin McGowan was close friends with the Steenburgs.

"My family is just going through a lot," Mrs Abeling said. "It's a horrible tragedy and there's no words to describe how we feel."

Was the limousine modified?

Officials have not yet said what caused driver Scott Lisinicchia to lose control, or why the accident was so deadly.

Many have speculated that the limo was modified in way to make it "stretch", which could also have caused it to lose some safety features.

After a crash in 2015 in Long Island's wineries region - which killed four bridesmaids - investigators in New York launched an investigation into the issue of unregulated modified limousines.

Officials found that modified limousines - which are banned or more highly regulated in several European countries - are made from vehicles that are often cut in half, and then have side panels added to elongate the cab.

But several safety features, such as rollover bars, reinforced doors, and side air bags, are removed in the process.

The National Safety Council's Deborah Hersman told CBS News they were "Frankenstein vehicles".