Updated

White House Press Secretary Jay Carney backed off comments that were construed as calling GOP presidential candidate Newt Gingrich a liar when he claims that if elected president, he would lower gas prices to $2.50 per gallon.

Carney said Monday that anyone who claims to be able to get gas prices down to $2.50 quickly is "lying." But on Tuesday, he backed away from that assertion.

"I said yesterday that anybody who said that would be a liar and I shouldn't have gone in motivations, I should have said anybody who says that doesn't know what he's talking about," Carney said at the daily press briefing.

President Obama has criicized the assertion that as president, Gingrich would lower gas prices to $2.50.

"First of all, while there are no silver bullets short term when it comes to gas prices," the president said during a February speech at the University of Miami. "And anybody who says otherwise isn't telling the truth," he added.

Gingrich lashed out at Carney's original comments Monday night, challenging the president to a debate on energy, giving suggestions for a location.

"I'd be glad to meet you at a oil rig somewhere, at a refinery, I'd be glad to meet you at a gas station, I'd even go to a university campus where you feel comfortable," Gingrich said.