SPOKANE, Wash. (AP) — GOP presidential candidate Newt Gingrich said Thursday a U.S. apology to Afghan authorities for burned Qurans on a military base was “astonishing” and undeserved.

Gingrich lashed out at President Barack Obama for the formal apology after copies of the Muslim holy book were found burned in a garbage pit on a U.S. air field earlier in the week

Obama’s apology was announced Thursday morning. A few hours later, news organisations reported that an Afghan soldier had killed two U.S. troops and wounded others in retaliation for the Quran burning.

Campaigning in Washington state, Gingrich said Afghan President Hamid Karzi owes the U.S. an apology for the shootings.

“There seems to be nothing that radical Islamists can do to get Barack Obama’s attention in a negative way and he is consistently apologising to people who do not deserve the apology of the president of the United States period,” Gingrich said.

“And, candidly, if Hamid Karzai, the president of Afghanistan, doesn’t feel like apologising then we should say good bye and good luck, we don’t need to be here risking our lives and wasting our money on somebody who doesn’t care.”

Even before Gingrich’s comments, White House spokesman Jay Carney sought to counter any criticism of the president’s apology. “It is wholly appropriate, given the sensitivities to this issue, the understandable sensitivities,” Carney told reporters traveling to Miami with the president on Air Force One.