"The helicopter was inside the pub. It's a mess. I could only get a yard or two inside. I helped carry people out."
Mr Murphy told Sky News that 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".
Grace MacLean, who was inside the pub, told BBC News: "They [the band] 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.
"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 First Minister said the Scottish Government's resilience operation has been mobilised.
"Our thoughts are with everyone involved with the incident in Glasgow," he said.
"However given an incident of this scale we must all prepare ourselves for the likelihood of fatalities."
One image of the crash showed the dark blue helicopter on the roof with yellow police insignia on part of the wreckage.
Helicopter operator Bond Air Services said it was working with Police Scotland.
A large section of the city centre was cordoned off with all roads leading to the junction of Clyde Street, Stockwell Street, Bridgegate and the Victoria Bridge closed.
Police have set up a telephone number for members of the public who are concerned about relatives who may have been involved in the crash. It is 0800 092 0410.
Retired firefighter Edward Waltham ran into the pub to help with the rescue effort and described how he pulled casualties out of the building.
"I helped grab a couple of people. One gentleman in particular who was completely covered in dust, who had very shallow breathing and appeared to be quite badly injured." he told BBC News.
"My initial reaction for him from my experience was to try not to move him because he had been in a crush situation.
"But as we were lying there other people were literally being pulled out of the pub and more or less thrown on top of us."