"I think the mistake that I made is to think that I was a spouse like any other spouse who could defend his candidate. I think I can promote Hillary but not defend her because I was President," Clinton said.

Clinton's comments while campaigning for his wife, including comparing Obama's bid to the unsuccessful campaign of an earlier black presidential hopeful, Jesse Jackson, resulted in a bitter war of words between the two top Democratic contenders.

But Clinton said on Friday that a lot of the media reports were ‘factually inaccurate’.

"I did not ever criticise Senator Obama personally in South Carolina. I never criticised him personally," he said.

"But I think whenever I defend her, I, A, risk being misquoted and, B, risk being the story. I don't want to be the story," he added.

"I need to promote her but not defend her. And I learned a very valuable lesson from all that dust-up."

Clinton also ruled out keeping away from Hillary's campaign, rejecting a suggestion from some quarters.