London (CNN) - A rescue operation was under way Thursday after part of the ceiling in the Apollo Theatre in central London collapsed during a performance, initially trapping people inside and causing casualties, officials said.
Authorities responded to a report of a ceiling collapse at about 8:15 p.m., police said in a tweet.
Within an hour, a spokesman for the fire department said all of the people who had been hurt - estimated at 20 to 40 - had been freed from the building, which had held some 700 theatergoers.