At least six people were feared dead on Saturday after a police helicopter crashed into a packed Glasgow pub.
Police have confrimed one death and the the toll is expected to climb, officials said Saturday.
As specialist search and rescue teams continued to probe the wreckage of The Clutha pub, Chief Constable Stephen House confirmed that overnight 32 people were taken by ambulance to hospitals in following the crash.
"Sadly at this time I can also confirm one fatality," he told reporters. "We expect that number to increase over the coming hours."
House said specialist teams are working to make sure everyone is recovered from the scene, where revelers were packed into the pub to hear a local ska band when the helicopter crashed through the roof.
Police couldn't say whether people were still trapped inside the pub, but the hope is to find survivors, he said.
"Highly trained firefighters from all over Scotland are carrying out rescue operations at the scene," House said. "They are continuing to make the building safe to allow full examination of the scene to ensure that everyone is recovered."
Sky News, citing unidentified sources, said there were at least six fatalities. There were three people aboard the helicopter.
"A full investigation is now under way. However, at this early stage it is too early to provide details on why the helicopter came down," said Deputy Chief Constable Rose Fitzpatrick.
"We are working hard to recover people still inside the building and we will make further details available when we have them."
As dawn broke, emergency workers were still labouring to free any people trapped in the rubble. The mangled helicopter was embedded in the pub's roof.
"We are in the process of making the building safe, it's very unsafe," said Assistant Chief Officer Lewis Ramsay, adding that rescue workers had been in contact with those trapped.
Witnesses described scenes of horror as the 12-metre helicopter carrying two police officers and a civilian pilot spiralled into the pub in a busy area of Scotland's biggest city, destroying part of the roof.
"It was fairly busy, we were all having a nice time and then there was like a whoosh noise," Grace MacLean, who was in the pub at the time told the BBC.
"There was no bang, no explosion and then there was what seemed like smoke and we were all joking that the band had made the roof come down and then it started to come down more and someone started screaming and the whole pub filled with dust and you couldn't see anything, you couldn't breath."
Police said it was too early to speculate on what caused the Eurocopter EC135 T2, made by a subsidiary of EADS, to smash into the pub.
The helicopter did not appear to have caught fire. The Air Accident Investigation Branch has begun an investigation.
"It looked to me like there would have been significant casualties from the speed the helicopter fell from the sky," said Gordon Smart, editor of the Scottish Sun newspaper who saw the crash.
"The sight of a helicopter falling from the sky will never leave me," he told the BBC.
There were around 100 people in the pub, listening to a concert by local band Esperanza.
"Our only concern now is for the safety and welfare of those less fortunate than ourselves," the band said on its Facebook website.
Caked in dust and blood, revellers rushed out into the street immediately after the crash.
Arriving by chance at the scene, a local member of parliament, Jim Murphy, said people had run to help rescue those inside.
"It's a horrible, horrible scene, but well done to the folk who were here. Everyone formed a chain of people from inside the pub to outside, and the fire brigade and everyone were here very quickly," said Murphy, who had blood on his shirt.
Photos taken at the scene by Twitter user Wesley Shearer showed a helicopter smashed into the roof of The Clutha pub. Emergency workers can be seen near the pub's door:
This is unbelievable. Just spent 20 minutes pulling people out the bar. Apparently a helicopter crashed on the roof. pic.twitter.com/4hoSwgwX2E
— Wesley Shearer (@scotscribbler) November 29, 2013
Twitter user Janney_h also shared an image of the scene taken from across the road:
— JanHollands (@Janney_h) November 29, 2013