Muhammad Ali, the legendary boxer who proclaimed himself “The Greatest” and was among the most famous and beloved athletes on the planet, died Friday in Phoenix, Arizona, a family spokesman said.

Ali, 74, had been at a Phoenix hospital since Thursday with what spokesman Bob Gunnell had described as a respiratory issue.

“After a 32-year battle with Parkinson’s disease, Muhammad Ali has passed away at the age of 74. The three-time World Heavyweight Champion boxer died this evening,” Gunnell said in a statement. “The Ali family would like to thank everyone for their thoughts, prayers, and support and asks for privacy at this time.”

A tweet on Ali’s official page posted a photo of the boxer and said simply, “Muhammad Ali. 1942-2016.”

Laila Ali “truly appreciates the outpouring of love for her family, as she spends quality time with her dad,” a statement issued by her business manager said.

Muhammad Ali also was hospitalised in January 2015 with a urinary tract infection. He was hospitalised in December 2014 with pneumonia.

Hours before her famed father passed away, Laila Ali posted a throwback photo of Muhammad Ali with her daughter, Sydney, who was born in 2011.

“I love this photo of my father and my daughter Sydney when she was a baby! Thanks for all the love and well wishes. I feel your love and appreciate it!!” Laila Ali, herself a former world champion boxer, wrote.

George Foreman, who Ali defeated in 1974 for the world heavyweight title, wrote on Twitter that “A part of me slipped away, “The greatest piece.” (CNN)

•Photo shows the late Muhammad Ali.