London :A packed London theater collapsed in the middle of a performance Thursday night injuring more than 80, sources said.At least seven of the injuries were described as serious. Police said they were not aware of any fatalities at this early stage.

Fire engines and police raced to the 775-seat Apollo Theatre on Shaftesbury Avenue in central London during the performance of “The Curious Incident of the Dog in the Night-Time.” Although first reports said the ceiling had collapsed, later accounts indicated it could have been a balcony or the roof.

Theatergoers reported people in the stalls had been hit by large chunks of falling debris.Authorities said all those trapped had been freed. Many of the injured were treated at a nearby theater.

Witnesses told sources that the theater in Londons famous West End was packed during the holiday season to see the show, which is based on the best-selling novel by Mark Haddon.