Updated at 7:00 a.m. Eastern.
(CBS/AP) KABUL, Afghanistan - Two U.S. troops were shot dead in southern Afghanistan when three assailants, two of whom were believed to be Afghan soldiers, turned their weapons against American troops on Thursday.
Afghan and U.S. military officials confirm to CBS News that the dead were U.S. troops, and that a third American service member was wounded in the attack. U.S. forces responded with gunfire and killed the two assailants in Afghan army attire, wounding a third Afghan shooter in civilian clothing.
Thursday's shooting is the latest case of Afghan policemen or soldiers — or militants disguised in their uniforms — killing NATO troops.
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Six Americans have now been killed and at least 15 wounded in attacks in Afghanistan since the Islamic holy books were burned at a U.S. base there. Dozens of Afghans have been killed or wounded in riots.
Two U.S. military advisers were shot and killed Feb. 25 inside their office at the Afghan Interior Ministry. Days before that, an Afghan solider shot and killed two other U.S. troops during a protest over the burning of Korans at a U.S. base.
The U.S. says the Korans were burned with trash by mistake, and multiple American officials - including President Obama - have issued apologies.
On Wednesday, "CBS Evening News" anchor Scott Pelley spoke to U.S. Ambassador to Afghanistan, Ryan Crocker, and Marine Gen. John Allen, the commander-in-charge of the war.
"Clearly it's been a bad week," Crocker told CBS News, "but I'm quite confident we'll get through this. The pace of protest has slowed dramatically. A decade's worth of relationships doesn't go away in a single week, so we'll move forward."
