M4 rifles and empty helmets sit in memorial to 5 soldiers killed in Afghanistan in August 2011. (Laura Rauch/Stars and Stripes)

IRBIL, Iraq — Two Americans were killed and five others wounded Sunday while conducting combat operations in northern Iraq, the U.S. military said.

In a statement, the U.S.-led international coalition Operation Inherent Resolve said initial reports indicated the incident was not due to contact with enemy forces. It is under investigation.

The statement did not name the slain soldiers, deferring identification to national authorities.

U.S. troops have been helping support Iraqi forces battling the Islamic State group — “a truly evil enemy” in the words of Lt. Gen. Stephen J. Townsend, Operation Inherent Resolve commander.

“The entire counter-ISIS coalition sends our deepest condolences to these heroes’ families, friends and teammates,” Townsend said in a statement. “There are no words to describe the respect I have for you and sorrow I have for your loss. I hope there is some small solace in knowing their loss has meaning for our country and all the nations of the coalition.”

After a nine-month battle to oust ISIS from its last urban stronghold in Mosul, Iraqi forces - closely supported by the U.S.-led coalition - are preparing to retake the ISIS-held town of Tal Afar west of the city.

The latest deaths bring to nine the number of Americans killed supporting Operation Inherent Resolve this year, including noncombat deaths. Nearly 50 Americans have been wounded in action since the anti-ISIS campaign began in August 2014, according to Pentagon data.

garland.chad@stripes.com Twitter: @chadgarland