MOUNT HOLLY, N.C. - In his latest jab at potential November rivals, President Obama on Wednesday hit Newt Gingrich for his $2.50 per gallon gas price proposal, telling an audience in a truck plant in North Carolina that it shouldn't listen to "phony election year promises."

The president made the jab while promoting what he calls an "all of the above" strategy to help lower gas prices - one that he says isn't just about drilling but transforming U.S. energy reliance toward alternative fuels, a prospect he acknowledged isn't going to happen overnight.

"The next time you hear some politician trotting out some three point plan for $2 gas you let him know we know better. Tell him we're tired of hearing phony election year promises that never come about," Obama said at a Daimler truck factory announcing incentives for fuel efficiency vehicles.

Obama didn't mention Gingrich by name but he has been liberal in attacking his potential election rivals in the last 10 days, taking time to go after them at official White House events like speeches to the American Israel Public Affairs Committee and the United Auto Workers. Wednesday's remarks came on the heels of Super Tuesday, in which Gingrich won his home state of Georgia. The UAW speech, in which he took two direct swipes at Mitt Romney, was delivered on the same day as the Michigan primary.

During a speech last week to a group bipartisan governors at the White House, Obama made a thorough clarification of his stance on higher education as including community colleges and other training programs. Many perceived that to be a reaction to criticism by Rick Santorum that the president was a "snob" because he thought everyone needed to go to college to get a job.

Officially, the White House says the president isn't focused on the campaign, even though he's held more than 100 campaign fundraisers since announcing his re-election bid nearly a year ago. Aides say he hasn't watched the 20 GOP debates, but rather catches news reports and that he'll be more fully engaged closer to convention time at the end of the summer.

Gas prices have been a hallmark issue of Gingrich's campaign. He has laid out a detailed strategy in speeches and referred voters to check out his website for a full analysis of his solutions.

The former speaker says his energy plan isn't so far-fetched. He notes when Obama came to office, a gallon of gas cost $1.89.

Mr. Gingrich responded to the president’s speech while speaking at a gas station in Pell City, Alabama by challenging the president to a debate at “any gas station in America.”

 “I want to start with this afternoon’s news that the President went to North Carolina and explained that you couldn’t get to $2.50 a gallon gasoline, and that that was just inaccurate for anybody to say that,” he said. “It’s so central to what’s wrong with America today. What’s wrong with America today is liberalism and what’s wrong with liberalism is that it’s just wrong about reality.”