Taliban spokesman Zabihullah Mujahid praised in a statement the "Afghan soldier" who carried out the attack. He did not claim the Taliban carried out the attack, although in the past the Taliban have encouraged such actions.
Such assaults are sometimes claimed by the Taliban insurgency as proof of their infiltration. Others are attributed to personal disputes or resentment by Afghans who have soured on the continued international presence in their country more than a dozen years after the fall of the Taliban from power.
Mark Jacobson, a former NATO deputy civilian representative to Afghanistan and now a senior adviser at the private Truman National Security Project, said the threat of Afghan troops turning their guns of their American partners is a serious problem.
"Any sort of insider attack, no matter who the victim is, is going to have an impact on the morale of soldiers," Jacobson said, adding that when a higher-ranking officer is killed, "you might see a wider impact on morale."
Foreign aid workers, contractors, journalists and other civilians in Afghanistan are increasingly becoming targets of violence as the U.S.-led military coalition continues a withdrawal to be complete by the end of the year.
Afghan President Hamid Karzai condemned Tuesday's attack as "cowardly."
It is "an act by the enemies who don't want to see Afghanistan have strong institutions," Karzai said in a statement.
The site of the attack is part of a military compound known as Camp Qargha, sometimes called "Sandhurst in the Sand"— referring to the famed British military academy — because British forces oversaw building the officer school and its training program.
Soldiers were tense in the immediate aftermath of the shooting. One soldier in a NATO convoy leaving Camp Qargha fired an apparent warning shot in the vicinity of Associated Press journalists who were in a car, as well as pedestrians standing nearby. AP photographer Massoud Hossaini said he and an AP colleague were about 15 feet from the soldier at the time. Hossaini said he thought the soldier fired a pistol.
"The vehicle before the last one, someone shouted at me," Hossaini said. "The last one, the soldier opened fire."
No one was wounded.
Elsewhere Tuesday, a NATO helicopter strike targeting missile-launching Taliban militants killed four civilians in western Afghanistan, an Afghan official said. NATO said it was investigating.
Burns and Baldor reported from Washington.
Associated Press writers David Rising in Berlin, Danica Kirka in London, Amir Shah in Kabul, Afghanistan, Jon Gambrell in Cairo. AP Radio correspondent Sagar Meghani and AP Researcher Monika Mathur in Washington contributed to this report.
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