Deadly operation targets the defenses of an oil field once controlled by the Islamic State militant group, reinforcing fears of an energized insurgency. Iraqi fire fighters battle a fire in the Alas oil field on Oct. 8, 2017, which was set ablaze by the self-proclaimed Islamic State group as it fled from Iraqi forces. (STAFF/Iraq Oil Report) At least four Oil Police officers died in an insurgent attack on the Alas oil field Tuesday, highlighting the ongoing security vacuum in rural parts of northern Iraq’s Kirkuk, Diyala and Salahaddin provinces. The attack comes after the U.S. military withdrew troops from northern Syria, raising fears in Iraq that the self-proclaimed Islamic State (IS) militant group could gain momentum. IS militants controlled much of the Alas field between 2014 and 2017, using rudimentary techniques to extract crude and help fund its war.