Witnesses described how a police helicopter dropped out of the sky and on to the roof of a pub “like a stone”.
Revellers at the Clutha bar, on the bank of the Clyde, were joined by passers-by as they formed a human chain to rescue unconscious victims in the immediate aftermath of the crash, which happened at about 10.25pm on Friday night.
Labour’s international development spokesman Jim Murphy said he saw a “pile of people clammering out” of the bar as he was driving past.
“I jumped out and tried to help,” he said.
“There were people with injuries. Bad gashes to the head. Some were unconscious. I don’t know how many.
“The helicopter was inside the pub. It’s a mess. I could only get a yard or two inside. I helped carry people out.”
He went on: “My human instinct kicked in. I didn’t like what I was seeing but I did what everyone else was doing and got stuck in. I feel like I’m in shock now. It’s a horrible scene.”
Mr Murphy told Sky News people formed a human chain to help pass unconscious people out of the pub so that “inch by inch, we could get the people out”.
Gordon Smart, editor of the Sun’s Scottish edition, saw the helicopter come down from a multi-storey car park around 250 yards away.
He told Sky News: “I was in a car park and looked up and saw a helicopter which I think was a police helicopter.
“It was just such a surreal moment. It looked like it was dropping from a great height at a great speed. I’m about 80% sure that it was a police helicopter.
“There was no fire ball and I did not hear an explosion. It fell like a stone. The engine seemed to be spluttering.”
According to their Facebook page, nine-piece Glasgow ska band Esperanza were playing at the venue.
Grace MacLean, who was inside the pub at the time of the crash, told BBC News: “There was a ska band on in the pub just at the back and it was fairly busy.
“We were all just having a nice time and then there was like a ‘whoosh’ noise – there was no bang, there was no explosion – and then there was some smoke, what seemed like smoke. The band were laughing and we were all joking that the band had made the roof come down.
“They carried on playing and then it started to come down more and someone started screaming and then the whole pub just filled with dust. You couldn’t see anything, you couldn’t breathe.
“It was a real testament to the people of Glasgow, everyone in that pub was shouting ‘here’s the door’, they were helping each other out.”
A message on the band’s Facebook page read: “Thanks for all the messages. I’ve just spoken to Jake and Jason. It seems that the band are all OK. Not so sure about everyone else.”
Ms MacLean said: “People started coming out with injuries and blood and everyone was going over and trying to help out.
“I don’t think it crashed, if it had crashed there would have been fire, there would have been a noise, but we didn’t hear anything, it was the smoke that we noticed.
“I think maybe whoever was in the helicopter just tried to land on the roof or something. The propellers could have been on but everyone seemed to be okay.
“I don’t know if anyone is trapped in there but there wasn’t anyone screaming for someone.”
Brendan Riordan, who was inside the pub at the time of the crash, told BBC News it had been “packed”.
He said: “It was quite hard to move in there with the amount of people enjoying the gig.”
He said he heard “a very loud bang” before a cloud of dust filled the pub.
“I was on the right side of the pub where the band were performing and the right side of the pub, if you look at the pictures which have come out now, you will notice that the right side of the pub did not collapse. It was more the central bit and the left side.
“After I exited the pub I saw people coming out covered in blood and covered in dust.
“There were people quite desperate and just before I left the inside of the pub I noticed that the ceiling had fallen towards the bar.
“People were not aware that a helicopter had crash-landed on the pub.”
Claire Morris, who lives near the Clutha bar, told BBC News: “We heard this bang. We didn’t really know what had happened and then we heard people coming out and screaming.
“I wasn’t sure whether there had been an explosion. My daughter said to me it was a helicopter that had hit the roof.”
“Police are everywhere. We are just very shaken.”