PALM BEACH, FLORIDA — Former New York City Mayor Rudy Giuliani was hospitalized on Sunday in Florida with pneumonia and remains in critical but stable condition, according to his spokesperson. Giuliani is now breathing on his own after being placed on mechanical ventilation, with his family and primary medical provider at his side.

"Rudy had a tough weekend. He had pneumonia," said Tom von Essen, who served as former Fire Commissioner of New York City during the September 11, 2001 attacks.

Ted Goodman, a spokesperson for Giuliani, said the illness progressed rapidly. "The virus quickly overwhelmed his body, requiring mechanical ventilation to maintain adequate oxygen and stabilize his condition." Goodman said Giuliani is "the ultimate fighter" and is "winning this battle."

Signs of illness were visible days before the hospitalization. Giuliani coughed as he began his online show on Friday. "My voice is a little under the weather, so I won't be able to speak as loudly as I usually do, but I'll get closer to the microphone," he said.

Giuliani has restrictive airway disease attributed to exposure to dust and toxins from the September 11, 2001, attacks on the World Trade Center. He earned the nickname "America's Mayor" after leading New York City through the aftermath of those attacks. Diseases caused by toxic dust and smoke from the attacks have continued to cause health issues among victims and first responders, and have claimed twice as many lives in the 25 years since the attacks as the attacks themselves.