A man who witnessed a bar fire in Switzerland has told Sky News he saw patrons walking over people as they tried to escape the packed venue.

This article contains details some readers may find distressing

Samuel Rapp, who was at a restaurant near Le Constellation bar in the Swiss ski resort of Crans-Montana when the fire broke out, described the scene as "horrible".

About 40 people were killed in the fire, police have confirmed, and 115 others injured - the majority seriously, suffering severe burns.

Mr Rapp said he was told of an "explosion" at the venue during the early hours of New Year's Day and went to investigate.

He told Sky News: "There were a lot of people at the entry trying to escape. And it was full and people [were] walking on everybody trying to escape.

"A lot of people were screaming trying to escape and I saw a lot of people on the floor."

Follow latest: Several dozen feared dead in fire

Footage of fire at Switzerland ski resort bar

Mr Rapp said he witnessed someone place a jacket over a victim's face and saw "a lot of people" whose hair had been burned off.

He said: "Some people were without clothes."

Asked what kind of people were at Le Constellation, he said: "Everyone in the world comes here."

He said a lot of people come from England, from the Netherlands, and from around Switzerland.

Mr Rapp added: "The people were between 16 and 18. It's horrible."

'I've spoken to a lot of traumatised people'

Sky News' Home Editor Jason Farrell is at the scene and said those he has spoken to have been left traumatised by the tragedy.

"It's just an absolute shock," he said, as people were gathering by the cordon closing off the area around the bar.

"There's still some waking up to this, this is a real shock to the people of Crans-Montana."

Image: The interior of the bar where the fire broke out. Pic: AP

Leon Christe, who works in Crans-Montana, told Sky News he was one of the first to the scene and tried to help as many people as possible by administering first aid.

He said: "It was very chaotic and very sad.

"Everywhere, there were young people who needed help, some had their clothes burned off.

"It was very traumatising."