NEW YORK – Joan Rivers' daughter released a statement Friday afternoon saying her mother's condition "remains serious."
“My mother would be so touched by the tributes and prayers that we have received from around the world. Her condition remains serious but she is receiving the best treatment and care possible," Melissa Rivers said. "We ask that you continue to keep her in your thoughts as we pray for her recovery.”
She had said late Thursdaythat Rivers. 81, was "resting comfortably" after being admitted to Mount Sinai hospital in New York earlier in the day, reportedly after she stopped breathing during throat surgery.
A source with knowledge of the situation told FOX411 that Rivers was in critical condition when she was taken to the hospital.
Police would not confirm Rivers' identity, but told FOX411: "An 81-year-old female was transported Mount Sinai in critical condition... at 9:39 a.m."Law enforcement said the woman was "unconscious and unresponsive."
The New York Fire Department added the person transported was in cardiac arrest.
TMZ reports Rivers stopped breathing during a throat procedure at a local clinic, and someone at the clinic called 911. E! News said Rivers was undergoing a minor endoscopic procedure.
Mount Sinai did not release any information about Rivers' condition.
"Her family wants to thank everybody for their outpouring of love and support," a rep for the hospital said. "We will provide an update on her condition as it becomes available.”
E! News reported Melissa Rivers rushed to New York to be with her mother. Rivers is the lead host on E!'s hit series "Fashion Police," which features a panels of celebrity commentators dissecting the outfits stars are spotted wearing.