Romney to Gingrich: Release Freddie Mac report

COLUMBIA, S.C. - Opening up a new line of attack against Newt Gingrich, Mitt Romney on Saturday called on his rival to release a report he gave to Freddie Mac concerning the past work he did for the mortgage giant.

Gingrich has come under criticism for taking taxpayer money to allegedly lobby on behalf of Freddie Mac, an institution that is unpopular with conservatives.

The former House Speaker has denied lobbying, and said his firm merely provided "historical advice."

"[Gingrich] said he was an historian and just provided historical information," Romney told a crowd at his campaign headquarters. "Then he said he told them what they were doing was somehow not going to work.

"I'd like to see the report. We've got a Washington insider talking about Freddie Mac. Let's see what his report was to Freddie Mac, what he said to them, what advice he gave them."

Gingrich's campaign did not immediately respond to a request for comment.

Sarah Huisenga contributed.