The United States should heed Afghan President Hamid Karzai's call to investigate the shooting deaths of nine civilians, including children, Human Rights Watch has said.
The organisation also said that it is concerned that the US military is "attempting to control information about the March 4 incident" by confiscating and deleting photo and video images taken by reporters on the scene.
On Sunday, as many as 10 civilians died from US troop fire in the wake of a suicide bombing in eastern Nangarhar province.
Witnesses said that US troops fired on the civilians as the troops sped away from the attack, which itself did not cause any deaths, Human Rights Watch said in a statement on Monday.
"Suicide bombers in Afghanistan regularly pose as civilians, but that doesn't give coalition forces carte blanche to respond with indiscriminate fire," Brad Adams, of the New York-based human rights watchdog, said.
"The fact that the insurgents violate the laws of war doesn't absolve the US and its allies of the need to observe them," Adams said.
HRW said eight to 16 people died in the incident, while Karzai's government put the toll at ten.
The groups also said US troops seized cameras belonging to a photojournalist and two local television camera operators and then deleted their images.