US music superstar Prince, whose hits included Purple Rain and Kiss, was found unresponsive on Thursday at his Minnesota home and was later declared dead, his publicist said. He was 57.

"It is with profound sadness that I am confirming that the legendary, iconic performer, Prince Rogers Nelson has died," said publicist Anna Meacham.

Celebrity website TMZ, citing sources close to the star, was first to report Prince's death at the home in Paisley Park, in the Minneapolis suburb of Chanhassen.

There were no immediate details on the cause of death, and the local medical examiner declined to comment.

Prince was an innovative and influential singer and songwriter whose music combined jazz, funk and disco. His hit songs also included Raspberry Beret and Little Red Corvette.

He first found fame in the late 1970s, and over the next three decades became known as one of the most inventive and eccentric forces in American pop music.

Prince, an intensely private person, sold more than 100mn records during his career, won seven Grammy awards and was inducted into the Rock and Roll Hall of Fame in 2004. He won an Oscar for best original song score for Purple Rain, the 1984 movie whose music was based on his album of the same name. Prince also starred in the movie.

In 2007, he played the Super Bowl in one of the most celebrated such performances.

Last week, the singer was briefly hospitalised with the flu after his plane made an emergency landing in Moline, Illinois, TMZ reported.

A representative told the celebrity news outlet that the singer had performed in Atlanta even though he was not feeling well and felt worse after boarding the plane for a flight back to Minnesota.

Prince's most recent album, HITnRUN: Phase Two was released in December 2015, and the artist had been on tour in the US as recently as last week.

In 1993, Prince legally changed his name to an unpronounceable symbol, but later changed it back again.

He was born Prince Rogers Nelson in Minneapolis on June 7, 1958, and is said to have written his first song at the age of 7. As well as singing and writing, he played multiple instruments, including guitar, keyboards and drums.

His music was marked by sexually charged lyrics and explosive live performances, while his private life was marked by a string of romances linking him with the likes of Madonna and Kim Basinger and Carmen Electra.

Prince was married twice: to his backup singer, Mayte Garcia, in 1996 and then to Manuela Testolini in 2001. Both marriages ended in divorce.

Twitter lit up with reaction from dismayed friends and fans. "Prince" was the top-trending term on the social media network in the US on Thursday afternoon with more than 840,000 mentions.

"And just like that ... the world lost a lot of magic. Rest in peace Prince! Thanks for giving us so much," tweeted pop star Katy Perry.

Retired basketball star Shaquille O'Neal wrote: "R.I.P PRINCE, another icon gone too soon."

Film director Spike Lee said on Twitter: "I Miss My Brother. Prince Was A Funny Cat. Great Sense Of Humor."