Rudy Giuliani, former mayor of New York City, is in the hospital “in critical but stable condition”, his spokesperson said on Sunday evening.

Ted Goodman, the spokesperson, posted on social media: “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. We do ask that you join us in prayer for America’s Mayor Rudy Giuliani.”

It is unclear why Giuliani, 81, is in the hospital or how long he has been there for.

Giuliani garnered acclaim for his response to the 11 September 2001 al-Qaida attack on New York City, earning the nickname “America’s mayor”.

Giuliani worked as an attorney for Donald Trump in his failed efforts to overturn the results of the 2020 election, an effort that led to criminal charges against Giuliani in two US states and a defamation lawsuit from election workers. Giuliani has denied wrongdoing in the criminal cases. Trump pardoned Giuliani after he faced criminal charges for his efforts to help try to overturn the 2020 election.

Trump, on his social media platform Truth Social, praised his former attorney: “Our fabulous Rudy Giuliani, a True Warrior, and the Best Mayor in the History of New York City, BY FAR, has been hospitalized, and is in critical condition,” he wrote on Sunday. He went on to say, without evidence, that Giuliani had been “right about everything” and that Democrats “did anything possible to destroy our nation, and now, look at Rudy. So sad!”

He was previously hospitalized last year following a car crash in New Hampshire.