Trailblazing comedian Joan Rivers has died in hospital a week after going into medical distress during a throat operation. She was 81.

Rivers died early Thursday afternoon surrounded by family and close friends at New York's Mount Sinai Hospital, her daughter, Melissa Rivers, said in a statement.

Rivers thanked fans for the “love, support, and prayers” they have offered from around the world.

“My mother’s greatest joy in life was to make people laugh,” Rivers said. “Although that is difficult to do right now, I know her final wish would be that we return to laughing soon.”

The sharp-tongued entertainer made audiences laugh with her quick wit and wry observations on life and love for 50 years, after being blessed by "Tonight Show" host Johnny Carson with the benediction: "God, you're funny."

Rivers, born Joan Alexandra Molinsky on June 8, 1933 to Russian Jewish immigrants, had dreams of being an actress while growing up in Brooklyn. She graduated from Barnard College in 1954, changed her name to Joan Rivers and hit the audition circuit, making small television appearances before learning that stand-up comedy would be a good way to earn money.

After she honed her act in comedy clubs, Carson put her on the "Tonight Show" in 1968. She never looked back.

Blazing a trail for women in the boys' club of comedy, Rivers became a permanent guest host of "The Tonight Show" until 1986, when she helped launch the fledgling Fox Network with "The Late Show Starring Joan Rivers." The show itself wasn't exactly a hit, and it ruined her relationship with Carson. He never spoke to her again.

But the native New Yorker found success in a number of endeavours, from daytime talk shows to Broadway, for which she enjoyed both commercial success and critical acclaim.

She won an Emmy for outstanding talk show host in 1989 for her second daytime show, "The Joan Rivers Show," and in 1994 was nominated for a best actress Tony for her Broadway turn in "Sally Marr and her Escorts," which she also co-wrote.

She made her Broadway debut in 1975 with another play she co-wrote, "Fun City," and returned to the Great White Way in 1986 to star in Neil Simon's "Broadway Bound."

In 1987 she suffered two crushing blows, first when she was fired from her late-night talk-show alongside her husband of 23 years, Edgar Rosenberg, who served as a producer. Three months later, he died of suicide.

"The trouble with me is, I make jokes too often," she told The Associated Press in a 2013 interview, days after the death of her old sister.

"I was making jokes yesterday at the funeral home. That's how I get through life. Life is so difficult -- everybody's been through something! But you laugh at it, it becomes smaller."

'She doesn’t know fear'

Rivers never let go of her small-stage roots, and maintained what for comics decades-younger would have been a punishing tour schedule. She regularly appeared at comedy clubs throughout North America and Great Britain, while writing 12 books, hawking her costume jewelry and other goods on the home shopping channel, and guest-starring in various television projects.

Somehow she kept working through myriad plastic surgery procedures, and her evolving look threatened to overshadow her work and talent. She never hid the fact that she was desperate to stay young in a business that doesn't treasure its elders.

Her desire to remain young, and her need to keep moving, was on raw display in 2010 in a brutally honest documentary "Joan Rivers: A Piece of Work."

In a review of that film, famed critic Roger Ebert also noted her fearlessness when she was on stage.

"She is a sadist of comedy, unafraid to be cruel -- even too cruel," he wrote. "She doesn't know fear. She seems to be curious about how far she can go and still get a laugh. That must feel dangerous on a stage with a live audience. Maybe she feeds on that danger."

The documentary followed a winning turn on "Celebrity Apprentice," in which she appeared with Melissa, one of many on-screen partnerships with her only child.

The two turned red-carpet arrivals at award shows into appointment television with their pre-show fashion specials before the Oscars and the Emmys. They later parlayed their on-screen partnership into a reality show, "Joan and Melissa: Joan Knows Best?" and "Fashion Police," a show in which the Rivers women and guest hosts critique celebrity fashion.

Last year, Rivers launched an online talk show called "In Bed with Joan," and entertains nearly 2 million Twitter followers daily with jokes and pictures from her travels.

All the while, she worked tirelessly for numerous charities, including the New York-based meal delivery service God's Love We Deliver, the American Foundation for Suicide Prevention, and Wounded Warriors.

"You want to see what it looks like to rage, rage against the dying of the light?" Ebert asked at the end of his review for 'A Piece of Work.' "Joan Rivers will not go gentle into that good night."

Rivers is survived by her daughter, Melissa, and her grandson, Cooper.