World mourns pop legend Jackson
Tributes from stars and fans have been pouring in for singer Michael Jackson, who has died aged 50 after suffering a cardiac arrest at his Los Angeles home.
Pop star Madonna said: "The world has lost one of its greats, but his music will live on forever."
Fans gathered outside the clinic where he was pronounced dead on Thursday. A post-mortem is taking place on Friday.
Los Angeles police have said the car belonging to a doctor has been towed away from Jackson's home and impounded.
Spokeswoman Karen Rayner said he was not under criminal investigation but the car "may contain medications or other evidence that may assist the coroner in determining the cause of death".
US authorities have said final results of the post-mortem examination could take up to eight weeks while toxicology tests are completed.
Jackson lawyer's 'medication warning'
Family lawyer Brian Oxman told US TV that he had been concerned about the star's use of pain relief medication.
Mr Oxman told ABC's Good Morning America programme that Jackson took prescription pain relief for injuries sustained earlier in his career, including bones broken in a stage fall.
"It caused him great pain. He just didn't like to feel such discomfort. He started taking pain medication. It became part of his life."
Mr Oxman added that he had warned that he "would not hold his tongue" about Jackson's use of medication in the event of the singer's death.
Paying tribute to the star, musician Sir Paul McCartney said: "I feel privileged to have hung out and worked with Michael. He was a massively talented boy-man with a gentle soul."
The singer's ex-wife Lisa Marie Presley said she was "sad and confused". "This is such a massive loss on so many levels, words fail me."
Pop star Justin Timberlake, who has been compared to Jackson, said: "We have lost a genius and a true ambassador of, not only pop music, but of all music."
The musician added: "He has been an inspiration to multiple generations."
MICHAEL JACKSON 1958-2009
Full name: Michael Joseph Jackson
Born: August 29, 1958, Gary, Indiana, US
Also known as: The King of Pop, Wacko Jacko
Biggest hits: I Want You Back, Don't Stop Til You Get Enough, Billie Jean, Bad, Black or White, Earth Song
Paramedics were called to the singer's Beverly Hills home at about midday on Thursday after he stopped breathing.
He was pronounced dead two hours later at the UCLA medical centre in west Hollywood. Jackson's brother, Jermaine, said he was believed to have suffered a cardiac arrest.
Speaking on behalf of the Jackson family, Jermaine said doctors had tried to resuscitate the star for more than an hour without success.
He added: "The family request that the media please respect our privacy during this tough time."
"And Allah be with you Michael, always. I love you."
Jackson, who had a history of health problems, had been due to stage 50 concerts at the O2 arena in London, beginning on 13 July.
Concerns were raised last month when four of Jackson's planned comeback shows were postponed, but organisers insisted the dates had been moved due to the complexity of staging the show.
Broadcaster Paul Gambaccini said: "I always doubted that he would have been able to go through that schedule, those concerts. It seemed to be too much of a demand on the unhealthy body of a 50 year old.
"I'm wondering, as we find out details of his death, if perhaps the stress of preparing for those dates was a factor in his collapse.
"It was wishful thinking that at this stage of his life he could be Michael Jackson again."
Following the news of his death, the singer's albums are currently occupying the top 15 slots of online music retailer Amazon.com's best-seller chart, led by his 1982 smash hit Thriller.
Bands playing at the Glastonbury Festival this weekend are also expected to pay tribute to Jackson's musical achievements.
Thriller Live, a tribute show to featuring the star's music in London's West End, announced it would go ahead.
A minute's silence will be held before the performance and the lights outside the Lyric Theatre, in Shaftesbury Avenue, will be dimmed as a mark of respect.
A special on the life and career of Michael Jackson will be screened on the News channel and BBC One at 1930 BST.
An additional scene has been filmed for Friday's episode of EastEnders which makes a reference to Jackson's death.
Jackson began his career as a child in family group The Jackson 5.
He went on to achieve global fame as a solo artist with smash hits such as Billie Jean and Bad.
Thriller, released in 1982, is the biggest-selling album of all time, shifting 65m copies, according to the Guinness Book of World Records.
Can't believe it. I'm gutted. RIP Michael, thanks for everything you gave us.Tommy, Cardiff
He scored seven UK number ones as a solo artist and won a total of 13 Grammy awards.
"For Michael to be taken away from us so suddenly at such a young age, I just don't have the words," said Quincy Jones, who produced Thriller, Bad and Off The Wall.
"He was the consummate entertainer and his contributions and legacy will be felt upon the world forever. I've lost my little brother today, and part of my soul has gone with him."
Jackson fans react to news of his death
The singer had been dogged by controversy and money trouble in recent years, becoming a virtual recluse.
He was arrested in 2003 on charges of molesting a 14-year-old boy, but was found not guilty following a five-month trial.
The star had three children, Michael Joseph Jackson Jr, Paris Michael Katherine Jackson and Prince Michael Jackson II.
Jackson's former wife Debbie Rowe is the mother of two of the children, and there is already speculation about who will gain custody of them.
He is survived by his mother, Katherine, father, Joseph and eight siblings - including Janet, Randy, Jermaine and La Toya Jackson.
Michael Jackson's career in numbers