"We were called to the Apollo Theatre in Shaftesbury Avenue to reports of a ceiling collapse during a performance. We are aware of a number of casualties, we don't know how many," the Scotland Yard spokesman told AFP.
Witnesses on local television and on social media said the incident happened during a performance of the hit West End show "The Curious Incident of the Dog in the Night-time".
Pictures on social media showed people fleeing the theatre with head injuries and covered in dust.
There were unconfirmed reports that part of the balcony had collapsed on members of the audience below.
"We were called to the Apollo Theatre in Shaftesbury Avenue to reports of a ceiling collapse during a performance. We are aware of a number of casualties, we don't know how many," the Scotland Yard spokesman told AFP.
Witnesses on local television and on social media said the incident happened during a performance of the hit West End show "The Curious Incident of the Dog in the Night-time".
Pictures on social media showed people fleeing the theatre with head injuries and covered in dust.
There were unconfirmed reports that part of the balcony had collapsed on members of the audience below.