Published: Aug 27, 2012 8:23 AM EDT

KABUL, Afghanistan (AP) - Military officials say 12 American soldiers have been killed by their Afghan colleagues this month. But local officials say the latest incident that happened today in Laghman province is a separate case from the rash of recent insider attacks, because it appears to have been an accidental shooting. A spokesman for the Afghan army corps in eastern Afghanistan says when a group of U.S. and Afghan soldiers came under attack, they returned fire and ran to take up fighting positions. But an Afghan soldier fell and accidentally discharged his weapon, killing two American soldiers with the errant rounds. The spokesman says when the commander of the unit started shouting at the Afghan soldier, he ran and was killed by air support.