A report by Afghanistan's Human Rights Commission, says US Marines violated international humanitarian law by using excessive force in reaction to a suicide bomb attack.
The US said that the fighting, near the city of Jalalabad, started when a convoy of marines was attacked by a suicide bomber and came under co-ordinated small-arms fire.
But the Afghan report said that the evidence of a complex ambush was 'far from conclusive'.
At least 12 civilians died and 35 were injured during the incident in March this year.
According to the authors of the report the marines fired indiscriminately on civilians and their vehicles as they left the scene.
Journalists also said that US soldiers deleted photos and videos, showing the aftermath of the violence.
