Army Col. Steve Warren told The Associated Press that Wheeler, 39, was killed a day earlier when he and dozens of U.S. special operations troops and Iraqi forces raided a compound near the city of Kirkuk, freeing approximately 70 Iraqi prisoners from captivity.
U.S. Secretary of Defense Ash Carter said he expected more raids of the sort, which he said had provided large amounts of intelligence for the coalition fighting Islamic State militants in the region.
Carter said he decided on the rescue mission after intelligence showed executions were imminent, including a grave that had been dug for the bodies. He said the body of the American soldier killed in the mission will be returned home on Saturday.
The Department of Defense said Wheeler died from wounds caused by small-arms fire during the operation. A native of Roland, Oklahoma, Wheeler is the first American to die in combat since the U.S. launched Operation Inherent Resolve, its campaign against the Islamic State group, last year. His identity was initially withheld pending notification of relatives.
He was assigned to the U.S. Army Special Operations Command in Fort Bragg, North Carolina.
The raid targeted a prison near the town of Hawija and was undertaken at the request of the Kurdish Regional Government, the semi-autonomous body that governs the Kurdish region of northern Iraq.
Pentagon press secretary Peter Cook said Thursday that U.S. special operations forces had been asked to support an operation to rescue fighters with the Iraqi peshmerga, the Kurdish region's organized militia. The Kurdish government later said that none of the hostages were Kurdish.
The raiders killed and captured a number of militants and recovered what the Pentagon called a trove of valuable intelligence about the terrorist organization.
U.S. combat troops have rarely, if ever, participated directly in combat against IS fighters on the ground since the U.S. mission began in 2014. The U.S. has mostly limited its role to training and advising Iraqi and Kurdish forces, airdropping humanitarian relief supplies and providing daily airstrikes in ISIS-held areas of Iraq and Syria.
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