Joan Rivers was hospitalized Thursday after she was rushed from a doctor's office when she went into cardiac arrest, police and hospital officials said.

In a statement, Melissa Rivers said her mother was "resting comfortably" with family. She did not elaborate on the 81-year-old comedian's condition.

"We ask that you continue to keep her in your thoughts and prayers," Melissa Rivers said. She offered thanks for the "overwhelming love and support for my mother."

Earlier Thursday, The Mount Sinai Hospital spokesman Sid Dinsay confirmed that Rivers was brought there in the morning.
 
New York City police officials, who spoke on the condition of anonymity because they weren't authorized to publicly name Rivers, said she was taken to the hospital just after 9:30 a.m. Thursday. It was unclear why she was visiting the doctor's office.

A red carpet regular 

The entertainer has logged a half-century in show business. She hosts Fashion Police on E! network and co-stars with her daughter, Melissa, on the WEtv reality show, Joan & Melissa: Joan Knows Best? She also presides over an online talk show, In Bed With Joan.

Melissa Rivers and Joan Rivers

Melissa Rivers, seen here with her mother Joan earlier this year, is reportedly on her way to New York. (Astrid Stawiarz/Getty Images)

Her latest book, Diary of a Mad Diva, was released this summer.

In 2009, Rivers emerged as the winner of NBC's The Celebrity Apprentice. A documentary, Joan Rivers: A Piece of Work, premiered in theatres in 2010.

Rivers coined the phrase "Can we talk?" in her standup routines and, interviewing fashionistas on the red carpet, introduced the question, "Who are you wearing?"

Brash style broke boundaries

A native of New York, Rivers originally entered show business with the dream of a theatrical career, but comedy became a way to pay the bills while she auditioned for acting roles.

"Somebody said, 'You can make six dollars standing up in a club,"' she told The Associated Press in 2013, "and I said, 'Here I go!' It was better than typing all day."

After proving herself in comedy clubs as a rarity — a woman comedian — Rivers was a smash on her first booking on The Tonight Show Starring Johnny Carson in 1965. "God, you're funny," Carson told her.

With files from CBC News