Kabul, Afghanistan (CNN) -- Two Americans and three Afghan soldiers died in a firefight that might have involved insurgent forces, the International Security Assistance Force said Sunday. One of the U.S. deaths was a soldier; the other was a civilian, U.S. officials said. The coalition first said the clash Saturday was the latest in a spate of insider attacks involving Afghan forces, which have killed more than 50 NATO troops this year. Later, the coalition called that into question. It appears the clash in Sydabad district might have been provoked by insurgent fire, said Lt. Gen. Adrian Bradshaw, the ISAF deputy commander, at a news conference.
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NEW: Gen. John Allen and President Hamid Karzai discuss security on "60 Minutes"
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Firefight may have been provoked by insurgents, ISAF commander says
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A civilian contractor killed in the clash was American, the U.S. Embassy confirms
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A U.S. service member also died in the Saturday incident, ISAF says
NATO's @placeholder troops are training Afghan soldiers and police to maintain security in the country ahead of the planned end of allied combat operations.