The hearse carrying boxing legend Muhammad Ali stops outside his childhood home where mourners wait to pay their respects on Friday in Louisville, Kentucky. Photo: AFP

Thousands of people from the worlds of sports, entertainment, politics and Muhammad Ali's native Louisville bid farewell Friday to the boxing legend eulogized by Bill Clinton as a "universal soldier for our common humanity."

A poignant memorial service, which began with a Koranic chant, capped two days of tributes honoring the three-time heavyweight world champion known as "The Greatest," who died last week at 74 after a long battle with Parkinson's disease.

Early Friday, thousands lined the streets of Louisville - the largest city in Kentucky, the southern state where Ali was born and launched his career - to catch a glimpse of the hearse carrying his remains, before a private family burial.

Then former US president Clinton, comedian Billy Crystal, Ali's wife Lonnie and others addressed mourners gathered at a Louisville arena - remembrances that lauded his athletic gifts, his passionate civil rights activism and his quick wit.

"We all have an Ali story. It's the gift we all have that should be most honored today," Clinton said. "Besides being a lot of fun to be around and basically a universal soldier for our common humanity, I will always think of Muhammad as a truly free man of faith."

Crystal, who brought some levity to the proceedings with comic impressions and a few well-received jokes, called Ali "a tremendous bolt of lightning created by Mother Nature, the fantastic combination of power and beauty."

Mourners chanted Ali's name as Lonnie took the stage, her face obscured by her wide-brimmed black hat.

She reminded the crowd, "If Muhammad did not like the rules, he would rewrite them. His religion, his name, his beliefs, were his to fashion, no matter what the cost."

Born Cassius Clay in 1942, Ali 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.

'He is an example' 

Earlier, fans along the funeral procession route, stretching about 30 kilometers, were in a festive mood - taking photos, cheering, applauding and chanting Ali's name in the bright sunshine. Some even wore boxing gloves in the heat.

The cortege passed by Ali's childhood home, the Ali Center, the Center for African American Heritage - which focuses on the lives of blacks in Kentucky - and along Muhammad Ali Boulevard before arriving at his final resting place, Cave Hill Cemetery.

Spectators threw red roses and other flowers onto the hearse, blocking much of its windshield by the time it reached its destination. A fleet of limousines transporting Ali's family and close friends followed.

"The kids love him, he's always stood for hope in this neighborhood," Toya Johnson said outside his boyhood home. "For the youth here, he is an example."

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 served as pallbearers.­

The interfaith memorial service led by an imam began in the mid-afternoon at a huge sports arena, bringing together VIPs and fans alike - more than 15,000 people in all.

"Muhammad Ali was the heart of this city - the living, breathing embodiment of the greatest that we can be," said rabbi Joe Rapport, one of several representatives of diverse faiths asked to speak, echoing Ali's message of tolerance.

Pallbearers place Ali's casket in the hearse as it prepares to begin a procession through Louisville on Friday. Photo: CFP

'Lost an icon'

Barack Obama was not present at the funeral of the man he calls a "personal hero" since it coincided with his daughter Malia's graduation from high school.

The US president's senior aide Valerie Jarrett, reading a message from Obama and wife Michelle at the service, said, "Muhammad Ali was America. Muhammad Ali will always be America."

"This week we lost an icon," Obama said Thursday in a video message ­honoring The Champ.

"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.

'Fly, butterfly, fly' 

On Thursday, thousands came together for an Islamic prayer service in remembrance of the champion, who converted to Islam in 1964, changing his name to Muhammad Ali.

Muslim men and women prayed in separate rows, most of the latter with their heads veiled.

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.

Friday's service had several emotional moments, including an impassioned tribute from Malcolm X's daughter Attallah Shabazz who fought back tears, and a poignant farewell from his daughter Rasheda.

"We love you so much, Daddy," she said. "And till we meet again, fly, ­butterfly, fly."