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FILE - In this Saturday, Feb. 16, 2019 file photo, U.S.-backed Syrian Democratic Forces fighters take a break as the fight against Islamic State militants continues in the village of Baghouz, Syria. U.S. and Iraqi officials say IS fighters facing defeat in Syria are slipping across the border into Iraq, where they are destabilizing the country’s fragile security. Hundreds -- likely more than 1,000 -- IS fighters have crossed the open, desert border in the past six months, defying a massive operation by U.S., Kurdish, and allied forces to stamp out the remnants of the jihadi group in eastern Syria. (AP Photo/Felipe Dana, File)

FILE - In this Saturday, Feb. 16, 2019 file photo, U.S.-backed Syrian Democratic Forces fighters take a break as the fight against Islamic State militants continues in the village of Baghouz, Syria. U.S. and Iraqi officials say IS fighters facing defeat in Syria are slipping across the border into Iraq, where they are destabilizing the country’s fragile security. Hundreds -- likely more than 1,000 -- IS fighters have crossed the open, desert border in the past six months, defying a massive operation by U.S., Kurdish, and allied forces to stamp out the remnants of the jihadi group in eastern Syria. (AP Photo/Felipe Dana, File)

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)