Two US soldiers were killed and one was injured while working on an operation in Afghanistan.
The operation was meant to target ISIS-K, an affiliate in the Achin District of Nangarhar Province.
A US official told CNN the members were Special Operations Forces soldiers.
The other soldier was wounded in the firefight, but their injuries weren't considered to be life threatening.
The Achin District is the main base for ISIS operations in Afghanistan and another US Army Special Forces soldier was killed there earlier in the month.
Afghan officials say the district is also where the US dropped a bomb that killed almost 100 ISIS fighters.
Commander of US forces in Afghanistan General John Nicholson says they are working to eliminate the affiliate this year.
“We’re going to keep going until they’re defeated in 2017.”
In early 2016, Afghan forces have worked with US military advisers to attack the ISIS troops and has since terminated half of their fighters and reclaimed two-thirds of their territory.