Obama, campaigning in Mississippi ahead of the state's contest on Tuesday, said he has won more states than Clinton and is leading in delegates who will decide the Democratic candidate to face Republican John McCain in November.

"I don't know how somebody who is in second place is offering the vice presidency to somebody who is in first place," Obama, an Illinois senator, told supporters. The crowd booed when he mentioned Hillary's idea.

"I'm not running for vice president. I am running for president of the United States of America," Obama added.

(Reuters, 3-10-08)