ORLANDO, Fla. — Rudy Giuliani told supporters Wednesday he's abandoning his bid for president and backing Republican rival and longtime friend John McCain.

Rep. Peter King, a New York Republican and adviser to Giuliani, said the former mayor called him this morning to tell him of his plan.

Giuliani "will be announcing his endorsement today," said King.

"I expect him to be fairly active for McCain. There is a real friendship and respect between the two," he said. A similar call took place between Giuliani and New York Senate Majority Leader Joe Bruno.

"I spoke with Rudy Giuliani this morning and he confirmed that he is dropping out of the race and will endorse Senator John McCain for president," Bruno said in a statement.

Once the Republican presidential front-runner, Giuliani suffered a debilitating defeat in Tuesday's Florida primary.

The former mayor finished a distant third to the winner, McCain, and close second-place finisher Mitt Romney. After the results, Republican officials had said Giuliani would endorse McCain on Wednesday in California.

The officials spoke on condition of anonymity in advance of the public announcement.

Speaking to supporters Tuesday night, Giuliani stopped short of announcing he was stepping down, but delivered a valedictory speech that was more farewell than fight-on.

"I'm proud that we chose to stay positive and to run a campaign of ideas in an era of personal attacks, negative ads and cynical spin," Giuliani said as supporters with tight smiles crowded behind him. "You don't always win, but you can always try to do it right, and you did."

Republican presidential candidates were scheduled to debate at the Reagan presidential library in Simi Valley on Wednesday night.

"I haven't talked to him," McCain said as he boarded a campaign charter plane Wednesday morning. "I'm going to talk to him today when we meet."

Separately, Giuliani said as he prepared to leave Florida for California Wednesday he was "not yet" ready to announce his intentions.

Tuesday's result was a remarkable collapse for Giuliani. Last year, he occupied the top of national polls and seemed destined to turn conventional wisdom on end by running as a moderate Republican who supported abortion rights, gay rights and gun control.

The results seriously decimated Giuliani's unconventional strategy, which relied heavily on Florida to launch him into the coast-to-coast Feb. 5 nominating contests.

But Florida proved to be less than hospitable. His poll numbers dropped and key endorsements went to McCain.