( CNN ) -- Comedian Joan Rivers is `` resting comfortably '' in a New York hospital after apparently suffering cardiac and respiratory arrest during a procedure at a medical clinic Thursday . Her daughter , Melissa Rivers , issued a statement on Friday . `` My mother would be so touched by the tributes and prayers that we have received from around the world , '' she said . `` Her condition remains serious but she is receiving the best treatment and care possible . We ask that you continue to keep her in your thoughts as we pray for her recovery . '' A law enforcement official told CNN that Rivers stopped breathing during throat surgery . Rivers , 81 , was taken by ambulance in critical condition to Mount Sinai Hospital in New York City . The clinic address given by a New York Fire Department spokesman is a building that houses an endoscopy clinic where doctors perform minor procedures on patients . The clinic is a mile away from the hospital . Rivers had been scheduled to perform her comedy act at the Count Basie Theater in Red Bank , New Jersey , Friday night . Michael Lucas , who was in the audience for Rivers ' show at New York 's Beechman Theater Wednesday night , told CNN that she joked about death . `` She said , 'You know I 'm 81 years old , and I could drop dead at any moment and you would be so lucky because you will have a story to tell your friends for the rest of your life , ' '' Lucas said . `` Then she mimicked people talking about what it was like to see her drop dead on stage . '' Rivers was in fine form , he said . `` There was no sign ( Wednesday ) night that she was declining . Her show was over an hour long and she never stumbled or even paused to catch her breath . '' In 2013 , Rivers allowed cameras to record a health scare for her and her daughter 's reality show , `` Joan & Melissa : Joan Knows Best ? '' Rivers said on the show that doctors found a spot on an X-ray after she had a persistent cough . `` We 're just not going to be sad about this , '' Rivers said during the episode . `` We 're gon na do jokes and be up until we know . That 's how I deal with things . I 'm not just gon na sit around the next couple of days and go crazy . '' Rivers has been open about her health issues . She was diagnosed with osteoporosis in 2002 after a fall down some stairs left her with broken bones , and she became an advocate for screenings for women . She also admitted to not being as healthy as she could be . `` I try not to be , but I 'm a terrible eater , '' she said . `` I wish I could say I eat super-healthy , but I do n't . I love junk food -- it should be its own food group -- so I help my bones with supplements and medicine . '' Joan Rivers 'stands behind ' Gaza quotes : 'War is hell '' See more comedian content at CNN Comedy . CNN 's Tony Marco , Lisa Respers France and Doug Ganley contributed to this report .
NEW : Daughter : `` Her condition remains serious and she is in intensive care. Her reality show documented a health scare last year . She has been open about previous health issues .