In an interview with ABC News, Newt Gingrich accused his Republican opponents of lying in their negative ads and offering "no hope they will be any good as president."

"Politics has become a really nasty, vicious, negative business and I think it's disgusting and I think it's dishonest," Gingrich told ABC News aboard his campaign bus in Iowa.

"And I think the people who are running the ads know they are dishonest and I think a person who will do that to try to get to be president offers you no hope that they will be any good as president," he said.

According to the Campaign Media Analysis Group, 45 percent of all campaign ads in Iowa this month have included attacks on Gingrich. Only 6 percent were pro-Gingrich. He acknowledges the ads have taken a real toll on his campaign.

"We're gradually going to have to figure out how to essentially take apart the negative ads," Gingrich, 68, said. "I mean I am committed to running a positive campaign and we have to find a way to communicate."

In an ABC News interview with Jake Tapper less than a month ago, Gingrich confidently predicted, "I am going to be the nominee."  Today he described his chances differently.

Today, he described his chances differently. "I think there's a very real likelihood that I can be the nominee but it's going to be a fight," Gingrich said.

No matter what happens in Iowa - even if he comes in fifth - Gingrich says the campaign will carry on.

"I'm going to survive, period. You're talking to somebody who in the national polls is tied for first or first. I think I'll survive OK. I think I'll survive," Gingrich said. "The next phase will be to go to New Hampshire and then after that you'll go to South Carolina and I think I will probably win South Carolina and I think by then we'll have figured out how to deal with each of these negative ads in a way that disposes them and how to communicate actively who are opponents are."

While the former Georgia congressman promises to stay positive, he lashed out at Rep. Ron Paul, saying it would be bad for the country if the Texas congressman won the Iowa caucuses Tuesday.

"I think it would be bad for the country," Gingrich said. "I think somebody who is for legalization of drugs and want to recognize, and doesn't mind if Iran gets a nuclear weapon is, would be bad for the country."