UPDATE: At 12:34PM ET on Aug. 28, E! News reporter Ken Baker tweeted that Joan Rivers was in stable condition.

Eighty-one year old comedienne Joan Rivers is in critical condition at a New York Hospital after she stopped breathing during throat surgery at a clinic in New York.

According to a report from CBS News, Rivers was taken to Mount Sinai Hospital earlier this morning (Aug. 28) after she stopped breathing during a procedure at a clinic.

According to TMZ, Rivers, who was undergoing a procedure on her vocal chords, is in critical condition. The TMZ report also says Rivers' heart may have stopped beating, though that has not been officially confirmed.