Spectators lined the streets, taking photos and chanting Ali's name.
Thousands of people lined the streets of Muhammad Ali's hometown Louisville on Friday to say goodbye to the boxing legend and civil rights hero, who mesmerized the world with his dazzling skills in the ring.
A funeral procession through town, a private burial and a public memorial service will wrap up two days of tributes to the three-time heavyweight world champion, who died last week at 74 after a long battle with Parkinson's disease.
Starting at 10:30 am (1430 GMT), a hour later than originally scheduled, the funeral procession started to wind through the city of 600,000 in the southern US state of Kentucky where Ali was born at a time of racial segregation.
The cortege will pass by sites that were important to "The Greatest": his childhood home, the Ali Center, the Center for African American Heritage -- which focuses on the lives of blacks in Kentucky -- and, of course, along Muhammad Ali Boulevard before arriving at the Cave Hill Cemetery for a hero's burial.
Spectators lined the streets, taking photos and chanting Ali's name. Some waiting near Ali's boyhood home carried signs and flowers in tribute to the boxing legend.
"The kids love him, he's always stood for hope in this neighborhood. For the youth here, he is an example," Toya Johnson, who wore an Ali T-shirt, told AFP.
Born Cassius Clay in 1942, the boxer won Olympic gold and went on to a glorious professional career, with his epic fights -- like the "Rumble in the Jungle" with George Foreman and the "Thrilla in Manila" with Joe Frazier -- now the stuff of sports legend.
He shocked America by refusing to serve in Vietnam, a decision that cost him his title and his career for years. He earned scorn for his incendiary comments about his opponents, once calling Frazier a "gorilla."
But Ali later earned global respect as a civil rights activist who preached religious tolerance, and for his public battle with a disease that ravaged his once powerful body.
Tyson joins pallbearers
Actor Will Smith -- who earned an Oscar nomination for his portrayal of Ali on the silver screen -- and former heavyweight champions Mike Tyson and Lennox Lewis will be among the pallbearers.
Tyson's participation was only confirmed early Friday.
"The grief that he showed was immense, he did not know at the time if he could do that emotionally... but apparently yesterday he decided he had to be here," family spokesman Bob Gunnell said.
An anonymous donor has pledged to cover the path to the grave with red rose petals.
On Friday afternoon, Ali will be honored at an interfaith memorial service at a large sports arena that will bring together VIPs and fans alike, with former US president Bill Clinton and comedian Billy Crystal to give eulogies.
Some 15,500 people are expected to attend -- with free tickets snapped up in a half-hour and a black market for the coveted tickets sprouting online.
Early Friday, T-shirt vendors were setting up shop along the procession route, some with equipment to make shirts on the spot.
'Lost an icon'
Barack Obama will not be present at the funeral of the man he calls a "personal hero" since it coincides with his daughter Malia's graduation from high school.
But the US president published a video message Thursday in which he displayed two mementos given to him by "The Champ" -- a book of photographs and a set of gloves -- which he has kept near to him through his time in the White House.
"This week we lost an icon," Obama said in the message. "A person who for African Americans, I think, liberated their minds in recognizing that they could be proud of who they were."
"I grew up watching him. I grew up having my identity shaped by what he accomplished," he said. "The incredible gestures of love and support that he showed me was one of the great blessings of my life."
Turkish President Recep Tayyip Erdogan had been scheduled to attend Friday's memorial service but cut short his trip to the US after a disagreement with funeral organizers, Turkish media reported.
Erdogan's bodyguards and US Secret Service agents had also clashed briefly at Thursday's Islamic prayer service as they jointly guarded the Turkish president, the newspaper said.
'Live his legacy'
On Thursday, thousands came together for the Muslim prayer service in remembrance of Ali, who converted to Islam in 1964, changing his name to Muhammad Ali.
The brief ceremony brought together dignitaries and ordinary fans, honoring a man known for both his tenacity in the ring and his social activism outside of it.
Muslim men and women prayed in separate rows, most of the latter with their heads veiled.
"There would be at least 60 people watching it on a small black and white television," mourner Babacar Gaye, a 54-year-old native of Senegal told AFP, recalling watching Ali fights at a house in Dakar as a teenager.
Imam Zaid Shakir, who helped organize the prayer service, said Ali had "a very, very special significance for the Muslim community."
"My hero was locked in his body," said Louisville taxi driver Fred Dillon, referring to Ali's fight with Parkinson's.
"Now he can float like a butterfly."