Comedian Joan Rivers has been hospitalised after she reportedly stopped breathing while undergoing surgery, according to officials.
Reports have suggested that the 81-year-old was in a critical condition, and has since improved. However, the hospital where Rivers was taken gave no details on her condition.
New York City Fire Department spokesman Jim Long said a patient reported to be in cardiac arrest had been taken from Yorkville Endoscopy to Mount Sinai by emergency workers responding to the call at 9:40 a.m. (13:40 GMT).
Rivers was having surgery on her vocal chords in a New York City clinic near Mount Sinai when she stopped breathing, according to the hospital.
The octogenarian was then rushed to hospital, with her daughter Melissa reportedly also on her way to her mother’s side, TMZ reported.
"Her family wants to thank everybody for their outpouring of love and support," hospital spokesman Sid Dinsay in a statement.
Rivers' representatives did not immediately respond to a request for comment, and a representative for her daughter declined to comment.
Ken Baker, an entertainment journalist at E! News, which features Rivers as host of its show Fashion Police, said on his Twitter account that Rivers was in stable condition.
Meanwhile, American TV host Billy Bush wrote on his Facebook page that Rivers' daughter Melissa had told him to "please pray".
He wrote: "Praying for Joan Rivers who is in critical condition at Mt Sinai hospital in NY. Texted with Melissa Rivers who said "please pray". Already doing that. Joan is beloved around here.
"A regular guest on Access Hollywood Live she never fails to deliver. She taped her post Emmy special Tuesday in LA and was strong. This is out of nowhere. Come on Joan you have to make it. Just think of all the material. Sending love and prayers."
Brooklyn-born Rivers is known for her acerbic tongue and is considered a pioneer for women in stand-up comedy.
In 2013, Rivers let cameras into her home for her reality show Joan & Melissa: Joan Knows Best?, during which she suffered a health scare.
Doctors had apparently found a spot on an X-ray after she had a bad cough.
“We're just not going to be sad about this,” Rivers said in the episode, according to CNN.
“We're gonna do jokes and be up until we know. That's how I deal with things. I'm not just gonna sit around the next couple of days and go crazy.”
She was diagnosed with osteoporosis in 2002 after she fell down some stairs and broke bones.
Additional reporting by AP