Two US soldiers have been killed and five injured during combat operations in northern Iraq.
Central Command said in a statement that five other soldiers were wounded in Sunday's incident, without providing further details.
The casualties were not due to "enemy contact" and that an investigation was under way, the United States military said.
The statement did not name the slain soldiers, deferring identification to national authorities.
"The entire counter-ISIS Coalition sends our deepest condolences to these heroes' families, friends and teammates", said Lt. Gen. Stephen J. Townsend, commander of Combined Joint Task Force - Operation Inherent Resolve, said in a statement. "There are no words to describe the respect I have for you and sorrow I have for your loss".
Almost 5,000 troops now remain in Iraq, as the USA military continues to assist and train members of the Iraqi military. The troops are mainly providing training and logistic support to the Iraqi forces, in addition to airstrikes by a US -led worldwide coalition.
Iraq's prime minister declared victory against IS in Mosul in July, and Iraqi forces are now preparing to retake the IS-held town of Tel Afar, to the west.