Tributes poured in from around the world Friday following the sudden death at 57 of superstar Prince, with fans flocking to dance parties to celebrate the life of the "Purple Rain" music legend.

As US authorities sought to shed light on the singer's mystery death in an elevator at his home in Minnesota, several buildings and websites were colored purple in memory of the performer hailed by President Barack Obama as a "creative icon."

In his hometown of Minneapolis, a huge crowd gathered outside the First Avenue club, where Prince recorded the film version of "Purple Rain," as well as outside the secluded compound where he was found dead Thursday.

Fans also gathered in other cities, including New York, where director Spike Lee led a Prince sing-along at a packed block party in Brooklyn.

Prince's death came just a week after the enigmatic Grammy and Oscar winner -- acclaimed for his guitar skills and soaring falsetto -- was taken to a hospital with a flu-like illness that he later downplayed.

"It is with profound sadness that I am confirming that the legendary, iconic performer, Prince Rogers Nelson, has died at his Paisley Park residence this morning," said his spokeswoman, Yvette Noel-Schure.

The Carver County sheriff's office in Minnesota said that deputies responding to an emergency call found an "unresponsive" Prince in an elevator.

Attempts to resuscitate him failed and he was pronounced dead at 10:07 am (1507 GMT), it said, adding that an investigation had been launched.

The sheriff's office released a transcript of a 911 call from an unidentified man at the property who was asked if he was with the patient. "Yes -- it's Prince," he replied.

The cause of death remained unclear. A spokeswoman for the Anoka County Midwest Medical Examiner's office told AFP that authorities would perform an autopsy on Friday.

Entertainment website TMZ, citing multiple unnamed sources, said the musician had been treated for a drug overdose in the week before his death, following a gig in Atlanta.

The singer was taken to hospital after his private jet made an unscheduled landing in Moline, Illinois, amid previous reports that he had been battling flu.

"Multiple sources in Moline tell us Prince was rushed to a hospital and doctors gave him a 'save shot'... typically administered to counteract the effects of an opiate," TMZ said.

AFP could not immediately verify the report.

- Creative icon -

Prince, a consummate live performer, became an international sensation in the 1980s, fusing rock and R&B into a highly danceable funk mix.

"Queen of Soul" Aretha Franklin led an outpouring of tributes from the entertainment industry, describing Prince as "an original and a one of a kind" and insisting his music would live on.

"He changed the world!! A true visionary. What a loss. I'm devastated," Madonna, a fellow 1980s icon who recorded with and briefly dated Prince, wrote on Instagram.

Rolling Stones frontman Jagger tweeted that Prince was "one of the most unique and talented artists of the last 30 years" while former Beatle Paul McCartney tweeted he had seen in the New Year with the singer and that he had "seemed fine" then.

"I never met Mozart, I never met Duke Ellington or Charlie Parker I never met Elvis But I met Prince," U2's Bono said in a tweet.

Actor Will Smith was among dozens of Hollywood stars who also reacted to the news on social media, saying he had spoken to Prince the night before and was shocked at the loss of the "beautiful poet" and "true inspiration."

Public Enemy frontman Chuck D lamented that it was like "the Earth is missing a note" while Lenny Kravitz thanked his "musical brother" who had shown him "the possibilities within myself."

In Minneapolis, authorities lit up a bridge in purple in Prince's memory, while Google's multicolored logo went magenta with animated raindrops lashing the letters.

The New Yorker also paid tribute, circulating a picture of the lavender cover with iris raindrops adorning its next issue due out Monday.

Prince -- whose huge catalogue of hits includes "1999," "Cream" and "Kiss" -- lived on the outskirts of Minneapolis, where he mostly kept to himself.

He changed his name in the 1990s to an unpronounceable "love symbol" -- prompting the media to call him "the artist formerly known as Prince" -- and wrote "slave" on his cheek to protest contractual conditions by his label Warner Brothers.

He was prolific in his output, recently releasing albums through streaming site Tidal, and had taken to scheduling shows at the last minute to avoid scalpers.

Obama, who invited Prince to play a private White House show last year, also lamented his passing.

"Few artists have influenced the sound and trajectory of popular music more distinctly, or touched quite so many people with their talent," Obama said.

"Prince did it all. Funk. R&B. Rock and roll. He was a virtuoso instrumentalist, a brilliant bandleader, and an electrifying performer."

- Dance parties -

In Minneapolis, thousands of fans thronged the First Avenue club, some carrying purple flowers. The atmosphere was carnival-like with the crowd erupting into renditions of his hits, including "Purple Rain."

"It's crazy how everybody is coming together like this. It's mind-blowing. I've never seen anything like it before," said Madalyn Holbeck, 22, who works in a store.

Fans also gathered outside his compound, where flowers were piled high along the fence.

Named after his jazz pianist and songwriter father's stage name, the pop icon was born Prince Rogers Nelson in Minneapolis, although his family had its roots in Louisiana.

In rare interviews he revealed that he suffered from epilepsy as a child but told his mother, jazz singer Mattie Della, that he had been cured by divine intervention.

Among his many achievements, one of the most frequently cited was a spellbinding guitar solo during a cover of The Beatles classic "While My Guitar Gently Weeps" at his induction into the Rock and Roll Hall of Fame in 2004.

He was in the middle of a pared-back "Piano and a Microphone" tour when he began experiencing health problems.

The musician invited fans via Twitter Saturday to a "dance party" at Paisley Park, where he kept his back recordings in vaults, in a bid to prove his health problems were behind him, Minnesota's Star Tribune newspaper reported.

"Wait a few days before you waste any prayers," he reportedly told the roughly 200 in attendance.