Giuliani's condition is reported to be serious but stable. However, it is still unknown why the 81-year-old was hospitalized or how long he has been there.
Giuliani, who previously served as President Donald Trump's lawyer, was elected mayor of the city in 1993.
"Our amazing Rudy Giuliani, a true warrior and by far the best mayor of New York City of all time, is being treated in the hospital," Trump writes on Truth Social.
