As many as three Afghan civilians have been killed when American troops opened fire after their vehicle struck a roadside bomb.
A man and his two sons were killed at their home in Ghani Khel, a district in the south of Nangarhar, on the border with Pakistan, said Attaullah Khogyani, a spokesman for the provincial governor.
"After the bomb blast hit them, the American forces then started shooting and killed one man and two children nearby," he said.
The US military command in Kabul said it was investigating the reports.
Civilian casualties have running at near record highs as fighting spreads to more areas of Afghanistan, according to the United Nations.
Afghan President Ashraf Ghani generally has been less vocal than his predecessor, Hamid Karzai, in publicly criticising the US military when troops are involved in incidents where civilians are killed.
On Saturday, three American soldiers were killed and one wounded when an Afghan soldier opened fire on them in Nangarhar, where elite US troops have been helping Afghan forces battle Islamic State militants.