Olympic gold medalist Mary Lou Retton has been battling severe pneumonia in a hospital intensive care unit, daughters of the famed American gymnast said.

A Tuesday post on a crowd-funding page by Retton's daughter, McKenna Kelley, characterized the Hall of Fame gymnast as being critically ill. Another daughter confirmed the illness to NBC News.

On the crowd-funding site, McKenna Kelley wrote: "My amazing mom, Mary Lou, has a very rare form of pneumonia and is fighting for her life. She is not able to breathe on her own. She’s been in the ICU for over a week now."