Rudy Giuliani, a former mayor of New York City, is in a Florida hospital in critical condition, his spokesperson said Sunday.

Spokesperson Ted Goodman would not specify which hospital and said Giuliani “remains in critical but stable condition.”

“Mayor Giuliani is a fighter who has faced every challenge in his life with unwavering strength, and he’s fighting with that same level of strength as we speak,” he said, before asking “that you join us in prayer” for the former mayor.

It is unclear what sent Giuliani, 81, to the hospital, and how long he has been there.

This article originally appeared in The New York Times.