New Mexico Gov. Bill Richardson on Wednesday sharply disputed Bill Clinton's reported claim that Richardson promised not to endorse Barack Obama's bid for the White House.

"I never did," Richardson told CNN. "I never saw [President Clinton] five times. I saw him when he watched the Super Bowl with me. We made it very clear to him that he shouldn't expect an endorsement after that meeting."

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In the interview Wednesday, Richardson acknowledged he was "very close to endorsing" Clinton, but decided not to after the campaign got "nasty."

"I held back. I waited. I felt the campaign got nasty. I heard Senator Obama; he would talk to me continuously," Richardson said.

"The Clintons should get over this," he added.