It wasn't immediately clear whether the ceiling or a balcony had collapsed.
The London Fire Brigade tweeted that all casualties who had been trapped under the debris were freed. They added they believed a ceiling had collapsed inside the venue.
Metropolitan Police tweeted that there were "more than 40 walking wounded being treated" at nearby Gielgud Theatre.
"Five people seriously injured. They have been taken to central London hospitals. Not aware of any fatalities at this early stage," police added.
For the full story: http://worldnews.nbcnews.com/_news/2013/12/19/21971742-londons-apollo-theatre-partially-collapses-during-performance
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