A roadside bomb hit a convoy of American soldiers in Nangarhar Province, in eastern Afghanistan, early Monday, according to Afghan officials in the area.
There was no confirmation of American casualties, but at least three civilians were killed when the soldiers opened fire after the explosion, said Ataullah Khogyani, a spokesman for the governor of Nangarhar.
The American military said it was aware of the reports and was investigating them.
All six of the American soldiers who have been killed in Afghanistan in 2017 died in Nangarhar Province, the most recent three on Saturday in an apparent insider attack. All were Special Operations soldiers fighting the Islamic State, which has a stronghold in the province.
In the latest incident, however, Zabihullah Mujahid, a spokesman for the Taliban, claimed responsibility for the attack, which took place in Ghanikhel District, not in the Islamic State stronghold of Achin District.