Riot police descended on a north London bingo hall as 700 youths turned the area into "a battlefield".
Officers attended the old Mecca bingo hall on Burnt Oak Broadway last night after reports of an illegal rave taking place.
When they arrived at the scene, they found 500 revellers inside the building, with 20 on the roof, and a group of around 200 outside the venue taking part in a "squat rave".
Residents reported hearing the police helicopter throughout the night and several youths climbing on roofs to escape the police.
David Norman tweeted: "At this rate with the helicopters and the riot police, Burnt Oak might as well be a battlefield."
Hundreds of revellers had gathered for the 'Summer Skankout', organised through Snapchat.
As police tried to quell tensions, revellers began hurling bottles at the officers.
Footage posted on Facebook group Inside Edgware showed a heavy police presence at the scene.
A Met Police spokesman said: "Borough officers spoke to the event organisers and tried to disperse the crowd, however more people started gathering and managed to get inside the building.
The spokesman added that riot police and the dog support unit were called to try and disperse the crowd.
"Bottles were thrown at police from the crowds in the area. No one was reported to have sustained any injuries."
Officers emptied the building around 2.40am and there are no reports of any arrests being made.
