Two US service members have been killed during combat operations in northern Iraq on Sunday, the coalition announced in a statement.
"Two U.S. service members were killed and five injured conducting combat operations in northern Iraq, Aug. 13, 2017", the U.S. Central Command said in a statement posted on its website.
"Initial reports indicate the incident was not due to enemy contact", the statement continued, adding the circumstances are "under investigation".
"There are no words to describe the respect I have for you and sorrow I have for your loss", said coalition commander Lt. Gen. Stephen Townsend extending his condolences to the families and fellow soldiers of those killed.
The incident came nearly one month after the Iraqi government declared victory over ISIS in the terror network's stronghold of Mosul.
The U.S. military announcement came as thousands of U.S. troops are participating in the war against the IS group in Iraq.
The fatalities bring the number of USA service members killed in 2017 while taking part of OIR up to nine, according to Stars and Stripes.