The operation targets militants who fled an earlier crackdown on the provincial capital, Ba'qubah.
Operation Lightning Hammer, which began overnight with an air assault, is part of a nationwide push called Operation Phantom Strike announced August 13 against Sunni and Shi'ite militants.
Meanwhile, the U.S. military said in a statement today that three U.S. soldiers were killed and another wounded in an explosion near their vehicle during maneuvers in northern Ninawa Governorate.
Another soldier was wounded and transported to a U.S. medical facility for treatment.
RFE/RL Iraq Report
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