NEW YORK -- He says he'd like to run for president. But Donald Trump says he's just "not ready to leave the private sector."

He announced today that he won't be seeking the GOP presidential nomination -- the announcement coming at a Manhattan hotel as NBC rolled out its fall lineup, including his show, "Celebrity Apprentice."

His office issued a formal statement in which Trump says he felt he could win the GOP nomination and the White House, but that he came to realize that a presidential campaign couldn't be run half-heartedly. Trump says, "Ultimately, business is my greatest passion."

Trump became known for re-igniting the "birther" controversy by insisting that questions were unanswered about whether Obama was born in Hawaii. Obama finally distributed his long-form birth certificate earlier this month. Trump took credit for it, even as it robbed his candidacy of its signature issue.

A few days later, NBC interrupted the airing of Trump's show with word of an Obama announcement -- about the killing of Osama bin Laden.