With two weeks to go until the crucial Iowa caucuses, Gingrich called upon Romney to state publicly that the super PAC, Restore Our Future, should stop running the negative television ads. He called Romney's claim that he's not legally allowed to communicate to the PAC a "dodge" -- and he said he would "disown" the organizers of his own super PAC, Winning Our Future, if it runs negative ads.

"I have a simple challenge for Governor Romney," Gingrich said at an appearance at a snow-removal equipment maker on the outskirts of Ottumwa. "This PAC was created by his former staff and funded by his personal friends. If he wants to stop it, he can say it publicly."

"I don't object to being outspent," Gingrich added. "I object to lies. I object to negative smear campaigns. And I object to things that the candidate himself refuses to support."