The Latest on the death of Muhammad Ali (all times EDT):
Journalist Jason Rezaian says that when he heard Muhammad Ali called for his release from an Iranian prison, it was a "turning point" for him.
Rezaian wrote in a Washington Post column that knowing Ali publicly acknowledged him was "everything to me."
Rezaian was arrested in July 2014. He was behind bars until January when he was released as part of a prisoner exchange between the United States and Iran. Officials never specified why Rezaian was arrested.
He learned of Ali's comments while imprisoned.
Rezaian wrote Saturday that since Ali is revered in Iran, several prison guards started to treat him with more respect.
"That Muhammad Ali, a black Muslim, is one of our great national icons speaks to what is right about this country," he wrote.
If there's one thing the candidates vying for the presidency agree on, it's that Muhammed Ali was The Greatest.
Campaigning in California ahead of the state's critical primary, Democratic front-runner Hillary Clinton remembered Ali with a subtle jab against the presumptive Republican nominee, Donald Trump.
Clinton said the U.S. is a country "where people can break down barriers, where they can worship their own God, where they can choose their own name."
Trump took to Twitter to remember the boxing great, saying Ali is "a truly great champion and a wonderful guy. He will be missed by all!"
Democrat Bernie Sanders also commemorated Ali with a jab at Trump: "He is, you know, what a hero, what a great man, and I say to all the people who are intimidated, and I've been all over the country and talk to Muslim people who say, 'You know, Bernie, our kids are now afraid.' I say to those people, one of the great American heroes in modern history was the great Muhammad Ali, a very proud Muslim. And don't tell us how much you love Muhammad Ali, and yet you're going to be prejudiced against Muslims in the country."
NBA Hall of Famer Jerry West got to know Muhammad Ali long before he was a heavyweight champion. West played for USA Basketball in the 1960 Olympics in Rome, when Ali was a young, up-and-coming boxer named Cassius Clay.
"I had heard of him a little bit, this kind of teenage sensation," West said. "Once you got there, my goodness, you could hear him coming from a mile away. A big smile, big personality, even then before he became a world champion. He was a magnificent person."
West saw Ali fight professionally several times and said: "I loved that guy. I really did.
"Being around him, you almost felt like a God-like presence," West said. "You really did. He had it. He had it."
Cleveland Cavaliers star LeBron James says he watched a replay of the "Thrilla in Manila" between Muhammad Ali and Joe Frazier after learning of Ali's death. James lauded Ali for taking a stand on social issues and said he tries to follow in those footsteps by using his platform to speak for what he believes in.
"When an icon like Muhammad Ali passes away, it's very emotional," James said a day before the Cavs play Game 2 of the NBA Finals against Golden State. "It's also gratifying to know that a guy, one man, would sacrifice so much in his individual life knowing that it would better the next generation of men and women after him.
"Today I can go to China and all over the world and people know my name and know my face. I give all credit to Muhammad Ali because he was the first icon. He is the GOAT. He's the greatest of all time and it has zero to do with his accomplishments inside the ring."
Civil rights leader the Rev. Jesse Jackson, a longtime friend of Muhammad Ali, says the boxer's impact extended far beyond the ring. He called the boxer a "social transformer" who used his fame to attack injustice during the civil rights struggle.
"From Texas across, from Florida up to Maryland, we couldn't use a single public toilet," Jackson said. "We couldn't use the libraries or the theaters or sit in the public parks. Ali identified with that struggle, used his person and his fame to illuminate that state of moral darkness in our country."
Jackson said he believed that decades later Ali reveled in being celebrated by those who once rejected him for his outspoken activism.
"That he had come full circle from being reviled to being revered, from being dismissed to being embraced," Jackson said. "I think he found a certain joy in that."
Basketball Hall of Famer Kareem Abdul-Jabbar says one of the many ways that he'll fondly remember Muhammad Ali is for how he liked to torment his opponents before fights.
"He would go to the training camp of his opponents and talk to them and torture them," Abdul-Jabbar told The Associated Press on Saturday. "I thought that was hilarious. Sonny Liston, he could have fried an egg on his head when he did stuff like that. I totally enjoyed that. He was kind of like acting up for all the rest of us ... kind of like our folk hero."
Abdul-Jabbar says he and Ali spoke many times about their shared Islamic faith, and how difficult it was at times to take unpopular stances. The NBA's all-time leading scorer says Ali had "incredible physical gifts" and that it was difficult and frustrating to watch Parkinson's disease affect the three-time heavyweight champion as much as it did in the final years of his life.
A family spokesman says Muhammad Ali died of septic shock "due to unspecified natural causes."
Spokesman Bob Gunnell says Ali, who had Parkinson's disease, died Friday at 9:10 p.m. Friday in Arizona, spending the last hour of his life surrounded by his family. He was initially hospitalized in the Phoenix area on Monday.
His funeral is scheduled for Friday afternoon at the KFC Yum! Center in Louisville, Kentucky.
Gunnell says Ali was a citizen of the world and he wanted people of all walks of life to be able to attend. The funeral will be translated and streamed on the internet.
A family spokesman says Muhammad Ali's funeral will be held Friday in Louisville, Kentucky.
The funeral scheduled for 2 p.m. at the KFC Yum! Center will be open to the public.
Eulogies will be given by former President Bill Clinton, Billy Crystal and Bryant Gumbel.
One of Muhammad Ali's daughters is describing her father's last moments, saying his heart wouldn't stop beating for 30 minutes after all of his other organs failed.
Hana Ali writes on Instagram that "no one had even seen anything like it."
She says the family was surrounding Ali, hugging and kissing him, holding his hands and chanting an Islamic prayer while his heart kept beating as his other organs failed.
She calls it a "true testament to the strength of his spirit and will."
San Jose Sharks coach Peter DeBoer isn't much of a memorabilia collector. A signed Quran he got as a 17-year-old from Muhammad Ali is one of the few items to make the cut.
DeBoer on Saturday recalled that chance meeting with the former heavyweight champion. He was attending his high school prom at the Royal Connaught Hotel in Hamilton, Ontario, some 30 years ago when he saw Ali enter.
DeBoer asked a member of Ali's entourage if he could meet the champ and was told to come to Ali's room with his friends in five minutes.
"He got out a Quran for each of us," DeBoer said before Game 3 of the Stanley Cup Final. "He wasn't preaching or trying to convert us, he just personalized each one for us, asked us some questions about what we were doing. It was an unbelievable life experience for me."
DeBoer said the only other memorabilia he has in his basement is a Wayne Gretzky stick, a Bobby Orr print and a Mike Weir Masters print.
Russ Greenleaf had planned to go to his synagogue in Louisville, Kentucky, on Saturday morning, but the 59-year-old instead attended a memorial service for Muhammad Ali.
"I thought God wants me to be here," he said. "This is the greater worship, really, to pay tribute to this great man."
Greenleaf stood in his Jewish prayer shawl and yarmulke to honor a Muslim who devoted his life to fairness for all colors and creeds. He said he especially admired Ali's conscientious objection to fighting in the Vietnam War.
"One of the most eloquent, down-to-earth statements I've ever heard is, 'I ain't got nothing against no Viet Cong,'" he said. "Few people could say it better than that. He gave up his career to take a stand against an unjust, immoral war when it was very unpopular to be saying what he said. He was dead right about it."
Daniel Wilson went to Muhammad Ali's boyhood home in Louisville, Kentucky, on Saturday to pay tribute to his old friend.
He was one year behind Ali at Central High School. He remembers that Ali was so committed to his conditioning that he didn't get on the bus; instead, he ran beside it, three miles, all the way to school each morning.
"The kids on the bus would be laughing," Wilson said, "and Ali would be laughing too."
The home was recently restored and is now a museum. Cars lines both sides of the street for blocks Saturday morning and dozens of fans walked around in the rain. One family came from St. Louis.
Flowers and signs piled up around the marker outside the little pink house on Grand Avenue designating it a historical site. Someone left a set of boxing gloves.
Roger Johnson was 17 with a leg injury and on crutches when he met Muhammad Ali on the boxer's estate in southwestern Michigan 's Berrien Springs.
"I watched him spar with Jimmy Ellis in his workout barn at his house," said Johnson, 56. "Back then, everybody knew who he was, but you didn't realize how big of a person he was. He came right through the crowd and shook my hand. He had the biggest hands of any man I'd ever seen."
More than that, Johnson and others in the small village say Ali's heart also was huge. The champ helped raise funds for a new high school track and donated items to auction for various causes.
Ali and his wife also donated a baseball field in 2003 to the nearby Niles Community Schools.
"He was a kind-hearted person," Johnson said. "There used to be a magic shop in town and he spent time there entertaining the kids with his magic. A lot of people knew Muhammad Ali. He would always sign boxing gloves and donate them to the auctions ... cancer fundraisers at my bar. We could always count on Muhammad Ali."
Ruby Hyde arrived at a memorial service in Louisville, Kentucky, clutching an old black and white photograph of a young Muhammad Ali.
She said she was a water girl during his amateur fights as a teenager in Louisville, taking water to the boxers between bouts.
"When he used to dance around the stage and fight the fighters the girls would be jumping up and down and clapping their hands," she said. "The other boxer would think that we're flirting with him."
Then Ali would turn around and knock him out, she said. Even then, she saw something special, something cerebral, about the way he fought.
Years later, he came back to the old neighborhood as a heavyweight champion, driving a Cadillac with the top down.
"All the kids jumped in and he rode them around the block," she remembered.
Employees at a Ramallah, West Bank, gym that offers kick-boxing classes said they had revered Muhammad Ali from childhood.
Twenty-five-year-old martial arts trainer said Ali "was more than an athletic champion."
"He was against racism and was a defender of Islam," Shkeir said between training sessions, adding that he watched Ali's matches on YouTube as a teenager.
Forty-eight-yaer-old Nizam Zayed said he watched most of Ali's matches.
"I used to watch him since TV was black and white," he said. "My generation liked Muhammed Ali because he was very good at boxing and because his name was Muhammed Ali and he was a Muslim."
Thousands are gathering at a London exhibition in Ali's honor — and remembering the 1963 Wembley Stadium fight that catapulted Cassius Clay to the brink of his first title.
Ali was unable to attend the late February launch of the 02 Arena "I Am the Greatest" exhibition highlighting his life story. Fans mourning his death toured displays Saturday showing his most famous TV interviews, his "fly like a butterfly, sting like a bee" robe and the split gloves he used to defeat British champ Henry Cooper by the narrowest of margins.
Cooper felled Clay in the 4th round with his trademark left hook and appeared on the verge of victory, but Ali trainer Angelo Dundee argued that one of Ali's gloves was torn and required replacement. The referee refused, but their argument bought Ali several extra seconds to recover. He then won a technical knockout of Cooper by opening a gash in the lighter, slower fighter's forehead.
Cooper lost to Ali again in London in 1966 and died in 2011. Ali later recalled how Cooper's left hook that felled him was so hard, "my ancestors in Africa felt it."
Two soccer greats are paying tribute to Muhammad Ali on social media.
Pele posted on Twitter and Instagram: "The sporting universe has just suffered a big loss. Muhammad Ali was my friend, my idol, my hero. We spent many moments together and always kept a good connection throughout the years. The sadness is overwhelming. I wish him peace with God. And I send love and strength to his family."
On Facebook, Diego Maradona wrote: "The best of all time has left. I remember the emotion of my dad when he saw him face to face in Las Vegas, in the fight between Sugar Ray Leonard and Tommy Herns in 1981. So how can I not feel this loss, if he was what he most admired my father? In the ring he was a dancer. Surely he left because he could no longer give us more happiness. My condolences to his family."
Louisville men's basketball coach Rick Pitino says the city celebrates the life of heavyweight boxing champion Muhammad Ali.
"He shined brightest in the ring and preached peace outside of it," Pitino said in a statement. "He loved babies, people and cherished his friends. We will miss you Champ. Rest in Peace."
Ali supported Louisville athletics and expressed encouragement in the wake of last fall's scandal surrounding Pitino's program with a tweet that said, "From one champion to another, I will always stand behind and support UofL. GoCards! #UniteLouisville."
Athletic director Tom Jurich says in a statement that his program is "deeply, deeply saddened" by Ali's passing and adds: "While he was undoubtedly one of the greatest athletes in history, the Champ made a difference in the lives of so many around the world. His generosity with his time for anything we asked of him — or things he offered to do without us asking — was incredible, as was the financial commitment he and (wife) Lonnie made to our baseball program at UofL.
Bill Clinton paid an emotional tribute to Muhammad Ali on social media.
The 42nd U.S. president tweeted: "Goodbye my friend. You were Great in so many ways."
Former heavyweight champion Mike Tyson also took to social media. "God came for his champion. So long great one," Tyson said in a tweet.
Madonna tweeted: "This Man. This King. This Hero. This Human! Words cannot express. He shook up the World! God Bless Him."
Anthony Carter scanned the line of people waiting to get into the Muhammad Ali Center in Louisville on Saturday morning. They were black and white, young and old.
"It's a beautiful thing to see," he said. "I think it shows unity that will last here in Louisville and will last hopefully across this country, especially at a tense time."
The 32-year-old from Chicago who now lives in Louisville said he wishes athletes today were as outspoken about equality as Ali, particularly about issues of police brutality and bias toward African-Americans.
"He stood up for us," he said. "But it was also for the tolerance of others who are white, who are Hispanic."
Muhammad Ali will be on the June 13 cover of Sports Illustrated for the 40th time in a photo shot by Neil Leifer while Ali trained in Miami Beach in 1970. "Muhammad Ali was a singular force of athletics, humanitarianism and social equality unlike anyone in our history," says group editor Paul Fichtenbaum.
President Barack Obama says Muhammad Ali "shook up the world and the world is better for it."
Obama says he keeps a pair of Ali's gloves on display in his private study, just off the Oval Office and under the famous photograph of the young champion "roaring like a lion over fallen Sonny Liston."
Obama says in a statement that Ali "fought for what was right," stood with Martin Luther King Jr. and Nelson Mandela "when it was hard" and "spoke out when others wouldn't."
Obama says even as Ali's physical powers were in decline, the boxing great "became an even more powerful force for peace and reconciliation around the world."
The president says Parkinson's disease may have "ravaged" Ali's body, but it "couldn't take the spark from his eyes."
Spectators at the English Derby, one of the biggest events in British horse racing, have honored Muhammad Ali with a minute's applause following the boxing great's death.
The applause took place before racing began Saturday, soon after Queen Elizabeth II arrived at Epsom racecourse.
One of Britain's top television interviewers, Michael Parkinson, had four verbal bouts opposite Ali — and described the fighter Saturday as the most memorable guest of his 40-year career.
Parkinson told the BBC that Ali's family recently asked him to provide audio recordings of all four interviews, so that Ali would listen to the decades-old discussions, which produced myriad clips highlighting his quick wit and indignation over racial discrimination.
"He was the most extraordinary man I ever met. He could be threatening. When I questioned him about his views on race, there was real anger in his response — and I looked into the eyes of somebody I thought might fell me in one blow," Parkinson said.
"That was just one aspect of a multi-faceted man and I loved him in a sense. When you look at all the thousands I've interviewed a few stand out. And he was the one that stands out most of all."
The head of the Nelson Mandela Foundation says the Nobel Peace Prize winner and former South African president called Muhammad Ali his boxing hero.
"Madiba had great respect for his legacy and spoke with admiration of Ali's achievements," Sello Hatang, the foundation's CEO, said in a statement.
A photograph of Ali and Mandela together sat next to the former president's desk at his foundation, the statement said, and Mandela's favorite book at the office in his later years was an autographed copy of the Ali biography "Greatest of All Time."
The statement included a comment Mandela made at an event in Washington in 1990: "There is one regret I have had throughout my life: that I never became the boxing heavyweight champion of the world."
Irish President Michael D. Higgins says the people of Ireland have awoken to news of Ali's passing "with the greatest sadness."
Ireland's ceremonial head of state called Ali a man of "wit, grace and beauty" who "brought his message of freedom and respect for people of all races to all the continents of the world."
Referring to Ali's long fight against Parkinson's disease, Higgins said the boxer inspired untold millions by displaying "courage in the face of great difficulties. He was intent on communicating right to the very end."
Ireland, a nation that long has punched above its weight in the ring, has harbored a love for Ali since his July 1972 fight in Dublin's Croke Park stadium against Al "Blue" Lewis. The western town of Ennis in 2009 named him its first-ever "freeman," an honor Ali accepted in person — nearly 150 years after Ali's great-great-grandfather Abe O'Grady emigrated from Ennis to America.
British boxer Amir Khan has paid tribute to Ali in a video message from his family's native Rawalpindi in Pakistan.
"Muhammad Ali was my hero. I'm so happy that I got to meet the guy," said Khan, who admired every aspect of Ali's game: his unique skillset, his confidence and his faith.
"He was one of the only fighters who predicted what round he was going to win and then knock his opponent out in that round. That's something you hardly ever see."
"He used to beat opponents with his mouth before he ever got into the boxing ring. He would win the fight before the fight even happened."
Khan, a British-born Muslim, said Ali showed courage for converting to Islam in 1960s America. "What he believed in, he did."
Tributes to Muhammad Ali rolled in from around the world Saturday, just hours after his death.
"The Greatest" had been hospitalized for respiratory problems Thursday, and news spread that this illness was serious. Late Friday, his family confirmed that he had died.
Reaction came in from around the world of sports, entertainment and politics. Former President Bill Clinton, who awarded Ali the Presidential Citizens Medal, mourned the death of the three-time heavyweight champion.
"Hillary and I are saddened by the passing of Muhammad Ali," Clinton said in a statement. "From the day he claimed the Olympic gold medal in 1960, boxing fans across the world knew they were seeing a blend of beauty and grace, speed and strength that may never be matched again."
A memorial service is scheduled for 10 a.m. in Louisville, Kentucky, Ali's hometown.