GLASGOW - A police helicopter smashed through the roof of a packed pub in Scotland's biggest city Glasgow on Friday and fatalities are likely, Scottish First Minister Alex Salmond said.
Emergency services declared a major incident at the Clutha Pub, where around 100 people were listening to a band play at the start of the St Andrew's Day weekend.
Witnesses said they saw the helicopter dropping like a stone from the sky, while people inside the pub heard a whooshing sound and then the roof caved in.
Police said there were two police officers and a civilian pilot on board the helicopter but did not give details of their condition.
"I can confirm that it is a police helicopter which has been involved in the tragic accident in Glasgow," Salmond tweeted.
"Rescue efforts in full operation. Given an incident of this scale we must all prepare ourselves for the likelihood of fatalities."
An AFP photographer said the helicopter appeared to have smashed through the top of the single-storey pub on the banks of the River Clyde, with a rotor sticking out of the roof.
Dozens of firefighters and paramedics were swarming around the scene, with emergency services also apparently securing the wreckage with cables and a cherry-picker.
Jim Murphy, a Labour party member of parliament and spokesman for international development, told the BBC he was driving through the area shortly after the incident.
"I jumped out and tried to help. There were people with injuries. Bad gashes to the head. Some were unconscious. I don't know how many," he said.
He said he and other people formed a human chain to get survivors out of the pub.
"The helicopter was inside the pub. It's a mess. I could only get a yard or two inside. I helped carry people out."
Grace MacLean, who was inside the pub at the time of the crash, told BBC News that the revellers were listening to a Ska band at the time.
"We were all just having a nice time and then there was like a 'whoosh' noise - there was no bang, there was no explosion," she said.
"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."
Scottish police said in a statement that the Eurocopter EC135 helicopter" came down on the roof of a pub in Stockwell Street at 10:25 pm", adding that it was a "major incident".
"Cordons have been put in place to allow the rescue operation to take place," it said.
Gordon Smart, editor of the the Scottish edition of Rupert Murdoch's Sun newspaper, said he saw the accident.
"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 per cent sure that it was a police helicopter," he told Sky News.
"There was no fireball and I did not hear an explosion. It fell like a stone. The engine seemed to be spluttering."
British Prime Minister David Cameron said: "My thoughts are with everyone affected by the helicopter crash in Glasgow - and the emergency services working tonight."
Scotland's Deputy First Minister Nicola Sturgeon said it was "awful news".
"Absolutely awful news about a helicopter crashing into the Clutha. All my thoughts are with everyone involved & the emergency services," she tweeted.