A police helicopter crashed late Friday night through the roof of a popular pub in Glasgow, littering the roof with debris and forcing injured revelers to flee through a cloud of dust. Scotland’s leader warned that fatalities are likely.

Photos of the scene aired on local television show what appear to be the helicopter’s propeller sticking out of the top of the pub’s roof. Rescue workers swarmed the door of the pub, and several fire trucks were on the scene.

First Minister Alex Salmond confirmed that a police chopper was involved in the crash, saying that rescue efforts at The Clutha pub in the city’s center were in full swing.

“Scottish resilience operation now mobilized,” he said on his official Twitter account. “Given an incident of this scale we must all prepare ourselves for the likelihood of fatalities.”

The helicopter had a crew of three — two police officers and a civilian pilot, according to Scottish police. Police said the aircraft was a Eurocopter EC135 T2 and came down around 10:25 p.m. local time. Emergency services responded immediately.

There were reports that people may have been trapped inside, but they could not be immediately confirmed. Glasgow ska band Esperanza was playing when the helicopter began to fall through the ceiling, witnesses said.

“It seems that the band are all OK. Not so sure about everyone else,” the band’s official Facebook page said.

Witnesses described a chaotic scene as people rushed through a cloud of dust to get out, some with bad gashes to the head and other injuries.

Grace MacLean, who was inside the pub at the time of the crash, said she was “having a nice time” when there was a “whoosh” noise — then smoke.

“The band were laughing, and we were all joking that the band had made the roof come down,” she told the BBC. “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.

People formed a human chain to help pass unconscious victims out of the pub so that “inch by inch, we could get the people out,” said Labour Party spokesman Jim Murphy, who happened to be in the area when the helicopter came down.

“The helicopter was inside the pub. It’s a mess. I could only get a yard or two inside. I helped carry people out,” Murphy told Sky News. “I saw a pile of people clambering out of the pub in the dust. No smoke, no fire, just a huge amount of dust.”

Gordon Smart, editor of the Scottish edition of the Sun newspaper, told Sky News that the helicopter “fell like a stone.”

“There was no fireball, and I did not hear an explosion,” he said. “The engine seemed to be spluttering.”

Prime Minister David Cameron tweeted: “My thoughts are with everyone affected by the helicopter crash in Glasgow — and the emergency services working tonight.”