Hillary Clinton on Wednesday reiterated her vow to stay in the Democratic presidential race, but she said it would be a "terrible mistake" for her supporters to vote for John McCain over Barack Obama.

"Anybody who has ever voted for me or voted for Barack has much more in common in terms of what we want to see happen in our country and in the world with the other than they do with John McCain," Clinton said on CNN's "The Situation Room."

"I'm going to work my heart out for whoever our nominee is. Obviously, I'm still hoping to be that nominee, but I'm going to do everything I can to make sure that anyone who supported me ... understands what a grave error it would be not to vote for Sen. Obama."

Clinton was responding to a question from a CNN iReporter who asked why she thought so many of her supporters would choose McCain over Obama.