Rick Santorum (AP)

The Obama campaign has shifted its focus to new GOP frontrunner Rick Santorum, slamming him for suggesting the president isn't a Christian.

Santorum fired back that he said no such thing, that he was discussing President Obama's liberal views, not this religious beliefs.

In Ohio over the weekend, Santorum told supporters at a tea party event that Obama's environmental views were harmful to the American people.

"It's not about you," Santorum said. "It's not about your quality of life. It's not about your jobs. It's about some phony ideal. Some phony theology. Oh, not a theology based on the Bible--a different theology."

The Obama campaign took to the airwaves, with Senior Campaign Adviser Robert Gibbs saying on "ABC This Week" that the remarks were "well over the line...it's wrong. It's destructive."

Santorum told CBS's "Face the Nation" that he "accepts the fact" that Obama is a Christian.

"I am talking about his world view...the way he approaches problems in this country. And I think they're different than how most people do in America," Santorum said.

A new Gallup poll shows Santorum leading Romney by eight points.