The assault late Sunday, the latest raid by US special operators on a mission to kill or capture IS leaders, occurred at an undisclosed location in northern Iraq and targeted Suleiman Abd Shabib al-Jabouri, Baghdad-based US military spokesman Colonel Steve Warren said.
He worked as "one of ISIL's military emirs and an ISIL war council member," Warren told Pentagon reporters in a phone call, using an acronym for the IS group.
"Al-Jabouri's removal will degrade ISIL's leadership network and impact their ability to coordinate attacks and defend ISIL strongholds," he added.
Warren declined to comment on whether Jabouri was killed, but in a statement to AFP on Wednesday the Kurdish regional security council said he died.
"Al-Jabouri, also known as Abu Saif, was a member ISIL's military council, supervising the group's activities in South Mosul and Makhmour. In the joint operation, two of his aides were also killed," the statement read.
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The raid was conducted by Kurdish fighters and elite US special operations troops deployed to Iraq as an "Expeditionary Targeting Force," or ETF.
Military officials keep the ETF's whereabouts secret, saying that discussing missions puts the elite fighters at risk.
The group works extensively alongside local Kurdish fighters.
Last month, Pentagon officials announced the ETF had captured a "significant" IS operative whose detention was expected to yield intelligence leading to the apprehension of other IS targets.
The United States has for the past 20 months led an international coalition against IS fighters in Iraq and Syria.
Defense Secretary Ash Carter on Monday announced several measures to help Iraqi security forces as they try to retake territory from the jihadists, including extra cash for the Kurds, additional US advisors and attack helicopters that could be used in an eventual battle for Mosul.