NEW YORK (AP) - Republican Sen. John McCain said he will officially enter the presidential race ... with a formal announcement in early April after a trip to Iraq.

The Arizona senator discussed the timing of the long-expected announcement with reporters at an awards reception Wednesday evening a few hours after taping an appearance on CBS' "Late Show with David Letterman."

On the talk show, McCain told Letterman: "I am announcing that I will be a candidate for president of the United States," then added that he would give a formal speech to that effect in early April.

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There had been no doubt that McCain would eventually become a full-fledged White House candidate, and he had been expected to make his candidacy official in the spring.

The 2006 midterm campaign had just ended when McCain took the first formal step toward a presidential run in November. He formed an exploratory committee and gave a speech casting himself as a "common-sense conservative" in the vein of Ronald Reagan who could lead the party back to dominance after a dreadful election season by returning to the GOP's core principles.

A political celebrity, McCain is considered a top contender for the nomination.