CALGARY - Over two dozen police cars along with numerous firefighters and EMS staff were needed to disperse a massive rave that got out of control in Calgary.

Police estimate there were close to 2,500 party-goers at the Symons Valley Ranch banquet hall on the outskirts of the city on Saturday night.

Insp. Rob Williams says organizers of the party called for ambulances when some of the people overdosed on ecstasy, and that the ambulance staff then called police.

Williams said he didn't believe the organizers had a permit for such a large party because he said police would need to be notified, and he says they weren't.

Police say about 11 people were treated for narcotics overdoses but Williams says none of them were life-threatening.

No one was arrested but Williams says shutting down such a large event put a strain on police resources.