Rescue workers examine the wreckage of a police helicopter which crashed onto the roof of the Clutha Vaults pub in Glasgow, Scotland November 30, 2013. REUTERS/Russell Cheyne One person was killed and at least 32 others were injured after a police helicopter crashed onto the roof of a bar in Glasgow, Scotland, Fox News reports.

Rescue efforts are ongoing, as an unknown number of people may still be trapped inside."Sadly at this time I can also confirm one fatality," Chief constable Stephen House told reporters, according to Fox. "We expect that number to increase over the coming hours."

The Guardian says the accident occurred during the middle of a concert, and quoted Jim Murphy, a Labour MP in the area at the time, that members of the public "formed a human chain to help get people out of the building." Murphy added that he saw "a pile of people" trying to escape the pub.

The bar is in downtown Glasgow, and the accident occurred at 10:24 p.m. local time.

"Part of the room was covered in dust," Fraser Gibson, an eyewitness told BBC. "We didn't know what had happened. We froze for a second; there was panic and then people trying to get out the door."

BBC reported at least 15 fire engines and 40 fire brigade staff on the scene attempting to rescue people. An eyewitness speaking to BBC estimated there were about 120 people inside the pub at the time of the crash.

The helicopter, a Eurocopter EC135 T2, had two police officers and a civilian pilot on board, according to AP.

"Given an incident of this scale we must all prepare ourselves for the likelihood of fatalities," Scotland's First Minister Alex Salmond told Reuters.

You can see Tweeted photos here, and here. Here's one photo from the scene:

ABC News picture of The Clutha Pub in Scotland where helicopter crashed on roof. Its thought to be a police chopper. pic.twitter.com/Mv6leuuuVx — Dan Lewis (@DanLewisNews) November 29, 2013

Scottish Sun editor Gordon Smart said he thought the helicopter was about to crash on top of him.

This is genuinely horrible. Spare a thought for those involved. Terrifying experience. Thought it was going to land on me. — Gordon Smart (@gordonsmart) November 29, 2013

British Prime Minister David Cameron has Tweeted about the incident:

My thoughts are with everyone affected by the helicopter crash in Glasgow - and the emergency services working tonight. — David Cameron (@David_Cameron) November 29, 2013

This is a developing story, and this post will be updated as we learn more.