WASHINGTON (Reuters) - The latest security crackdown in one part of Baghdad has led to significantly fewer attacks on U.S. and Iraqi forces with improvised explosive devices, an American Army commander said on Friday. Col. J.B. Burton, who heads a brigade patrolling a 36-square-mile (93-square-km) area of western Baghdad where about 1 million people live, cautioned that difficult work lay ahead and that the United States was not declaring victory. "It is important to note that the overall effects of this new Baghdad security plan ... will not be seen in days or weeks, but over the course of months,"...