George Foreman said: "Muhammad Ali was one of the greatest human beings I have ever met"
Boxing stars have been paying tribute to the sporting legend Muhammad Ali who has died at the age of 74.
Former heavyweight boxing champion Evander Holyfield said: "I'm glad to have known Ali because when I was a kid, at eight years old, I was told I would be like Ali.
"To take it upon yourself and say; 'I'm the greatest', you put yourself in a position for people to take pot shots at you.
"This is what Ali did. It's amazing him becoming three-time heavyweight champion of the world. At that time people thought, 'Who could beat three?
"You have to be stronger to get up from a loss to go on and that's what Ali proved to be."
Speaking to Newstalk, Irish boxer and 1992 Olympic Gold medal winner Michael Carruth said: "He was a role model for everyone of us. He stood up for his beliefs, not just inside the ring, but outside the ring as well.
"His skills inside the ring will never be matched. He's known as the Greatest, and we will always be the Greatest":
Boxing champion Floyd Mayweather Jr said: "There will never be another Muhammad Ali. The black community all around the world, black people all around the world, needed him. He was the voice for us. He's the voice for me to be where I'm at today.
"I just want to thank Muhammad Ali and his family for being such strong people. You will always be missed. My prayers go out to Ali and his family."
George Foreman, Ali's friend and rival from the famous "Rumble in the Jungle" fight, said: "We were like one guy - part of me is gone.
"Muhammad Ali was one of the greatest human beings I have ever met. No doubt he was one of the best people to have lived in this day and age.
He also spoke of Ali's love for the UK and the way he was treated in the country.
"He loved London. If he had been born and raised in London he never would have changed his name," he said.
Mike Tyson tweeted:
Fellow boxing champion Roy Jones Jr tweeted:
My heart is deeply saddened yet both appreciative and relieved that the greatest is now resting in the greatest place.— Roy Jones Jr. (@RealRoyJonesJr) June 4, 2016
"May God bless the family and all of us that are left behind that were Tributes have flooded in from the sports world and beyond for Muhammad Ali.deeply touched by his life. There will never ever be another one like him."
Argentinian boxer Marcos Maidana, a two-weight former world champion, tweeted: "Muhammad Ali the all-time greatest has left us. Thanks for everything. Go with God."
Philippine boxer and politician Manny Pacquiao said: "We lost a giant today. Boxing benefited from Muhammad Ali's talents but not nearly as much as as mankind benefited from his humanity."
Ali's former promoter Don King said: "He's always been right there, Johnny on the spot, anything he could do for the benefit of mankind.
"Let us celebrate his life. This is not a time to mourn. This is a time to try to emanate the job he was doing and the burden he leaves behind for us to carry on, to remember that the people are the most important."
Retired Irish boxer Barry McGuigan hailed Ali as "a remarkable human being".
He said: "He was hugely inspirational for me and many fighters all over the world. Everybody wanted to box because of him."
"He was just so amazing in every way. More than anything else it was how humble and how brilliantly charismatic he was.
"He was a beautiful looking man, a beautiful looking individual and he had so much compassion."
He added: "He was the greatest sportsman there has ever been and we were very lucky that he chose boxing."
Former boxing champion Oscar De La Hoya tweeted:
Legendary boxing trainer Freddie Roach said: "Our condolences and our thoughts and prayers go out to all who mourn and are affected by the loss of #MuhammadAli"
Boxing promoter Kellie Maloney said Ali was an "icon".
She said: "He transcended boxing, took it to a new level. He was the first real superstar, not just in boxing but in sport.
"If you asked my daughters who the favourite sportsman in the world is, they'd say Muhammad Ali. He didn't just win battles in the ring, he won battles outside of the ring."