01/06/2012 04:55 pm ET Updated Jan 06, 2012

Newt Gingrich: Mitt Romney 'Ought To Run A Campaign Worthy Of His Grandchildren'

Newt Gingrich sharply criticized Mitt Romney Friday over negative ads run by a Romney-aligned super PAC in an interview with MSNBC's Chris Matthews Friday.

The former House speaker said it was like "Saturday Night Live" for the group to question his conservative credentials. He added, "[I] thought to myself, let me get this straight -- this is a guy that didn't support Reagan in the 80s, said in '94 he didn't want to go back to Reagan policy, votes for Paul Tsongas in '92, who appointed liberal judges, has tax-paid abortions, put Planned Parenthood into Romneycare, and he's questioning whether I'm a conservative?"

Gingrich challenged Romney to run a campaign "worthy of his grandchildren." He continued, "He ought take those ads home and show them to his grandchildren. Grandpa did this, what do you think of this kind of trash on television -- someone being beaten up like this on television?"

The group's ads blanketed Iowa, contributing from Gingrich once being seen as a frontrunner to finishing in fourth place in the Iowa caucus. The group is running newspaper ads in New Hampshire and South Carolina linking Gingrich to President Barack Obama. The group has also purchased airtime in Florida and spent $86,000 on ads in South Carolina through Jan. 5.

Romney criticized super PACs in an MSNBC appearance last December. "They've set up these new entities, which I think is a disaster, by the way. Campaign finance law has made a mockery of our political campaign season. We really ought to let campaigns raise the money they need and just get rid of these super PACs," he said. Romney took advantage of an FEC loophole to address (but not solicit funds at) a fundraising gathering for the group last July.

When asked whether he would tell the group to stop running the anti-Gingrich spots, he said it was illegal to coordinate with them. However, Romney could make a public statement criticizing the negative ads without running afoul of the law.

Gingrich said Romney should have admitted that the ads were his. "I took Romney head on about this because it's all baloney. That was his staff from last campaign with millionaire friends paying for it. Those are his ads. He did not have the guts to admit it."