Boxing icon Muhammad Ali died as a result of septic shock, according to a family spokesman. Ali, who passed away late Friday aged 74, will be laid to rest in Kentucky next week.
Former boxing champion Muhammad Ali died of "septic shock due to unspecified natural causes," family spokesman Bob Gunnell said at a press conference on Saturday.
Ali had been admitted to an Arizona hospital earlier in the week, but his condition quickly deteriorated.
"We still had a lot of hope it was going to turn around," Gunnell said. "His final hours were spent with just immediate family," he added. "He did not suffer."
The three-time world heavyweight champion and outspoken civil rights activist died Friday night at the age of 74. He had long suffered from Parkinson's disease, and had been hospitalized a number of times in recent years.
"He'll be remembered as a man of the world who spoke his mind and wasn't afraid to take a chance and went out of his way to be a kind, benevolent individual that really changed the world," Gunnell said.
Tributes flow in
Tributes have been pouring in from around the world for Ali, who is being hailed as one of the greatest sports stars of the 20th century.
"Muhammad Ali was The Greatest. Period," US President Barack Obama said, praising the boxer's integrity and saying he "stood up when it was hard; spoke out when others wouldn't."
Ali's hometown of Louisville, in the US state of Kentucky, lowered flags to half-mast in his honor on Saturday, while fans flocked to his childhood home, now a museum, to pay their respects. The boxer's body was to be taken there in the next two days.
Funeral in Louisville
A public funeral and memorial is planned to take place in Louisville on Friday, following a private service for family members, Gunnell said.
"A rather large funeral procession will take Muhammad Ali through the streets of Louisville to allow anyone that is there from the world to say goodbye," Gunnell said. He noted also that the service would be conducted in the presence of an imam and in accordance with "Muslim tradition."
Former US president Bill Clinton, comedian Billy Crystal and sports journalist Bryant Gumbel will offer eulogies for the boxing great.
Ali was born in Louisville on Jan. 17, 1942, as Cassius Marcellus Clay Jr - a name shared with a 19th century slavery abolitionist. He changed it to Muhammad Ali after converting to Islam in 1964.
Ali had been living in the Phoenix area with his fourth wife, Lonnie, who knew him when she was a child in Louisville. He is also survived by his nine children.