IS-K or Islamic State Khorasan is the Afghan affiliate of the Middle East-based terrorist group.
Achin district administrative chief Ismail Shinwari confirmed the incident but did not elaborate further saying still there is no information available regarding the cause of the incident and possible casualties.
He said there had been a "shooting incident" after which United States forces conducted an airstrike targeting the militia.
On the other hand, the Taliban group claims that the attack was carried out by one their fighters who had managed to infiltrate among the public uprising forces ranks. An AFP reporter saw at least eight militia fighters buried this morning. One-third of the 21 American soldiers killed in combat in 2017 in Afghanistan died in Nangarhar, making it the deadliest province for the USA military.More news: Rio Tinto to sell aluminium smelter for $US500m
Tom Gresback, a USA military spokesman in Afghanistan, told the Associated Press one US service member was wounded and in stable condition in what he would describe only as "active ground engagement".
The Pentagon has announced that they are investigating an incident in which a U.S. soldier was wounded after being shot by a pro-government Afghan militia in the Nangarhar Province.
Gresback did not disclose which branch of the military the troops were from.
So-called "green-on-blue" attacks in which Afghan forces turn on their comrades or their Western counterparts have been a major problem during Nato's long years in Afghanistan.More news: 2nd Gen HBM2 Aquabolt Starts Mass Production
While Afghan security forces are conducting most of the fighting against IS and Taliban militants, U.S. troops operate alongside them in a training capacity and are frequently on the front lines.
A local MP claimed two USA soldiers were killed in the incident, though the Pentagon denied any troops were killed, and only one wounded.
The attack came hours after the provincial government announced in a statement that Afghan forces killed almost two dozen Taliban insurgents, including four commanders, in the nearby Khogyani district.
A New Year's Day attack on a military patrol in Achin killed one US soldier.More news: Trump's 'S***hole' Comment May Have Won Back Ann Coulter