NEW YORK -- Stumping for Donald Trump in Ocala, Florida, on Wednesday, former New York Mayor Rudy Giuliani told a crowd that Hillary Clinton had falsely claimed to have been in New York on Sept. 11, 2001 -- an incorrect claim he took back a few hours later.

"I made a mistake. I'm wrong and I apologize," Giuliani told The Associated Press.

In Florida, addressing what he portrayed as Clinton's past remarks on the subject, Giuliani said: "Don't tell me, if you said that, that you remember Sept. 11, 2001. I remember Sept. 11, 2001. Yes, yes, you helped to get benefits for the people that were injured that day. But I heard her say one day she was there that day. I was there that day. I don't remember seeing Hillary Clinton there."

In fact, she wasn't in New York, but she never claimed to be, either.

On many occasions, Clinton has described being in Washington, D.C., on Sept. 11 when hijacked jets struck the World Trade Center and the Pentagon. She was a member of the Senate at the time, and Congress was in session.

The next day, commercial flights remained grounded but Clinton travelled to New York City aboard a government plane. There, she circled the smouldering World Trade Center in a helicopter, then toured ground zero with Giuliani and New York's Republican governor, George Pataki.

Photos of that tour show Clinton standing shoulder to shoulder with Giuliani.

Asked about his comments, Giuliani said he thought he had heard Clinton say during the last presidential debate that she was in New York on 9-11. But after being contacted by a reporter, he reviewed a transcript and found out he was wrong.

Told that he was being criticized online by people posting photographs of him with Clinton at ground zero, Giuliani was contrite.

"I probably deserve it," he said.

After returning to Washington, Clinton worked with other lawmakers to secure billions of dollars in federal aid for New York to assist in the city's recovery.

In his speech in Ocala, Giuliani questioned Clinton's commitment to people killed or injured in the attacks.

"Don't tell me you subscribe to the notion that all of us who lived through Sept. 11th and were lucky to be alive and have lost so many friends," he said. "I lost so many friends on Sept. 11th. I think about it every day. Don't tell me you belong to our very, very tight group of Never Forget!"