UPDATE: Roughly 80 walking wounded and seven people more seriously injured have been treated following a ceiling collapse at London's Apollo Theatre, London fire and ambulance officials said. Around 720 people were in the theater at the time of the collapse, which "took parts of the balconies down with it," the London Fire Brigade said in a press release.
(CNN) -- Between 20 and 40 people have been injured in the Apollo Theatre ceiling collapse, the London Fire Brigade tweeted from their official account Thursday.
The Press Association said witnesses saw people emerging from the building covered in dust.
The theater's website said "The Curious Incident of the Dog in the Night-Time" had been playing," which it described as "a thrilling new stage play from the National Theatre."
Ticket prices at the theater, which opened its doors in 1901 and whose 775 seats are arrayed on four levels, included a 1 pound "theatre restoration levy," the website said.
It is owned and operated by Nimax Theatres.
WATCH VIDEO: Eyewitness Hannah George says "the ceiling basically collapsed" at London's Apollo theatre and there was "dust everywhere" with ushers shouting "out,out,out."