Gingrich denounces negative Iowa mailer sent by super PAC supporting him

Republican presidential candidate Newt Gingrich today denounced a flyer, sent by a so-called super PAC that supports his campaign, calling his GOP rival Mitt Romney "the second most dangerous man in America."

The flyer, NBC News first reported, charged that Romney "is the second most dangerous man in America and will perpetuate Obama's slide into financial crisis." At a stop in Mason City, Iowa, Gingrich said he is standing by his promise to disavow groups that attack his GOP opponents on behalf of his campaign.

"I would encourage them not to do that anymore," Gingrich said of the Strong America Now flyer. "I think that's not right, and I don't - you know, again, I don't control them, but I would discourage them from that kind of negative information. I think that's wrong."

When speaking for himself, Gingrich does largely avoid taking slamming his opponents -- though he doesn't completely shy away from criticizing the other candidates. However, voters in Iowa and elsewhere aren't just relying on direct face-time from Gingrich or the other candidates to form their opinions. They have been flooded with campaign information on television, online, and via mailers, which all possibly could influence their vote.

What Iowans are getting in the mail

CBS News/ National Journal campaign reporter Sarah Huisenga contributed to this report.