Romney, in an interview with Fox News, said he doesn't believe Reid has a credible source but urged the Senate Democratic leader to reveal who it is.
"I don't really believe that he's got any kind of a credible source," Romney said. "I don't know who gave him this line of reasoning, whether it came from the White House or the DNC or a staffer, but he ought to say where it came from, and then we can find out whether that person has any credibility. I know they don't."
He said Reid also has "lost a lot of credibility."