Spokane, Wash. -- Newt Gingrich sharply criticized President Obama for penning a letter to Afghan President Karzai expressing "deep regret" for a reported incident at Bagram Air Base where copies of the Koran were burned.

"The president apologized for the burning, but I haven't seen the president demand that the government of Afghanistan apologize for the killing of two young Americans," Gingrich said, referring to two soldiers serving in the U.S.-led coalition force who were killed by an Afghan wearing an army uniform during a third day of riots over the burning of Islamic scripture.

U.S. officials have said the books were burned by mistake and the case is under investigation, but the apologies and Karzai's call for calm have yet to quell the protests that have boiled over in Afghanistan. White House Press Secretary Jay Carney defended the president's letter, noting that Dana Perino apologized on behalf of President Bush in 2008 after a U.S. serviceman shot a Koran.

Gingrich said, "My hunch is, since the person who killed them is an Afghan soldier, that that soldier was being paid with American money, armed with American money, trained with American money, and there is something profoundly wrong when the commander in chief refuses to defend the integrity and the lives of the people who serve under him.

The Republican presidential candidate, who has accused the administration of "routinely and consistently" lying to the American people about the threat of Islamic radicalism, continued, "There seems to be nothing that radical Islamists can do to get Barack Obama's attention in a negative way and he is consistently apologizing to people who do not deserve the apology of the President of the United States, period."

"And candidly," Gingrich continued, "If Hamid Karzai, the President of Afghanistan, doesn't feel like apologizing then I think we should say goodbye and good luck, we don't need to be here risking our lives and wasting our money on somebody who doesn't care." The audience cheered

Gingrich said President Obama "surrendered twice today," first in the letter and secondly in an energy speech he delivered Thursday in Miami.

"The president went to Miami to explain rising gas prices. I was just reading the text -- I kid you not, this is one of those things that is truly worthy of Jay Leno and Letterman. The president of the United States explains first of all there's no single silver bullet. Now that's just wrong. Defeating Obama is a single thing that would change everything," the candidate said.

Gingrich vowed to bring America back to a "pre-Obama" world of energy policy, mocking President Obama for pointing to algae as an alternative source of fuel.

"For the president to stand there and explain to us that sometime in our children's lives, algae would rescue us -- I mean I rest my case," Gingrich said, couching his remarks first by saying he is "pro-science," supports research and has a friend who is working on long-term projects to convert algae into usable energy.

In a speech on gas prices at the University of Miami Thursday, President Obama defended his efforts to invest in energy alternatives and mocked Republicans for their "three-point plan for $2 gas."

"I'll save you the suspense. Step one is to drill, and step two is to drill, and step three is to keep drilling," Obama said, and in a veiled reference to Gingrich, remarked, "Anyone who tells you we can drill our way out of this problem doesn't know what they're talking about -- or just isn't telling you the truth."

Approximately 550 people turned out to see Gingrich at the Bing Crosby Theater, a mix of high school seniors from area schools -- many of them self-described Democrats -- and older audience members who said they planned to participate in the caucuses next week.

"I think it's too early to rule him out. The media tried to rule him out in June," said Leroy Simpson of Omak, who drove three hours with his wife to see the candidate. "I've known Newt since the 90s. I think he's the best candidate."

"We have been following all the debates. He would absolutely smash Obama," said his wife Lorna.