American troops conducting an operation in Afghanistan's eastern Nangarhar province were "engaged by direct firing" — and numerous reports indicate the United States suffered multiple casualties.

The Military Times reported that "numerous" U.S. personnel were killed in the attack. The Associated Press also reported that numerous Americans were killed and injured.

Military spokesman Col. Sonny Leggett confirmed American troops were "engaged by direct firing," but did not provide additional details.

"We are assessing the situation," he said.

More from the New York Times:

Details of the incident, in Nangarhar Province where American Special Forces were helping Afghan commandos and the Afghan Army clear an area threatened by the Taliban, were scarce. It was not clear whether the firefight was the work of Taliban infiltrators, a major concern in the past, or the result of an argument between allied forces that turned deadly.



Two Afghan officials said five or six American soldiers and six Afghan soldiers were killed. A United States military official said there were at least six American casualties and confirmed that they included fatalities but did not say how many.

Indeed, Mohammad Ajmal Omar, a member of Nangahar's provincial council, told the Washington Post the attack was possibly a "green on blue" insider attack.

Both the Taliban and the Islamic State have a foothold in Afghanistan. ISIS, in particular, controls a significant portion of the Nangarhar Province.