(CNN) - Sen. Barack Obama Monday flatly rejected suggestions that he would be a vice presidential running mate for Sen. Hillary Clinton.
Both Clinton, Obama's rival for the Democratic presidential nomination, and her husband, former President Clinton, have suggested a joint Clinton-Obama ticket - with Obama in the second slot.
"Senator Clinton is fighting hard. She's tenacious. I respect her for that. She is working hard to win the nomination. But I want everybody to be absolutely clear. I'm not running for vice president. I'm running for president of the United States of America," Obama told supporters during a rally in Columbus, Mississippi.