Defense officials say they are investigating an incident in which air-strikes were called in on hostile forces that attacked a group of U.S. and Afghan troops.
U.S. officials are trying to determine the exact identities of what are termed "enemy forces" who opened fire on coalition troops near the city of Khost in eastern Afghanistan.
A Pentagon spokesman says the coalition troops consisted of friendly Afghan troops accompanied by American soldiers. They were fired upon on Saturday while investigating a fortified roadblock.
One of the Afghan troops was killed and three others wounded in the incident.
The Pentagon says coalition forces attempted to negotiate the surrender of the estimated 40 enemy gunmen but the effort was rejected. U.S. air-strikes were called in on the enemy positions both Saturday and Sunday.
The New York Times says the strikes appear to differ from previous American bombing raids. It quotes Afghan commanders in the area as saying the strikes were aimed at controlling clashes among rival militia groups -- not at hitting Taleban or al-Qaida forces.
The Pentagon is not commenting on the report directly.
But a spokesman says any forces that fire on U.S. troops and the Afghan fighters with them are deemed to be hostile and can expect retaliation.