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Iraqi forces are deployed during an offensive to retake Mosul from Islamic State militants outside Mosul, Iraq, Monday, Oct. 17, 2016. Columns of Iraqi and Kurdish forces backed by U.S.-led airstrikes slowly advanced on Mosul from several directions on Monday, launching a long-awaited operation to retake Iraq's second largest city from the Islamic State group. (AP Photo/Khalid Mohammed)

Iraq War

President Obama announced on Oct. 21 that the United States is pulling all its troop from Iraq by the end of the year. (ABC News)