Rick Santorum defended comments he said about President Barack Obama's beliefs, saying Sunday he was criticizing the president's liberal world view rather than his religious ideology.

On CBS's Face the Nation, the Republican presidential candidate, known for his strong social conservative views, said he believes the president is Christian, despite interpretations of a comment he made at a campaign stop in Ohio on Saturday.

I've repeatedly said that I believe the president is Christian, he says he is a Christian, but I am talking about his world view, the way he approaches problems in this country, and I think that they're different that most people do in America, Santorum said.

The former Pennsylvania senator first drew ire on Saturday when he said Obama's agenda is based on some phony theology. Not a theology based on the Bible. A different theology.

Many in the media interpreted the statement as an attack on Obama's religious beliefs. The Obama campaign quickly hit back with a response. The latest low in a Republican primary campaign that has been fueled by distortions, ugliness and searing pessimism and negativity, the statement read.

Obama campaign Adviser Robert Gibbs also said on ABC This Week on Sunday that Santorum's statement was a low blow.

I can't help but think that those remarks are well over the line, Gibbs said. It's wrong. It's destructive.

Santorum first made the statement in conversation about the White House's energy policy. On Sunday, he told CBS' Bob Schiffer that policy based on global warming was harmful to society and business.

When you have a worldview that elevates the Earth above man and says that we can't take those resources because we're going to harm the Earth by things that frankly are not scientifically proven ... this is all an attempt to give more power the government.

Santorum's surge in a number of polls have put him back into the spotlight, leading the Obama campaign and his GOP rivals to step up their attacks against him.

 A new University of Texas/Texas Tribune poll puts Rick Santroum in the lead ahead of Mitt Romney, Newt Gingrich and Ron Paul at 45 percent. A new Public Policy Polling survey on Michigan published Saturday has Santorum leading with 37 percent in the state, ahead of Mitt Romney's 33 percent.

Calculations made by New York Times statistician Nate Silver gave Rick Santorum a 72 percent chance of winning the Michigan primary, a 92 percent chance of winning Ohio and 50 percent chance of winning Oklahoma.