KIFL, Iraq, March 29 (Reuters) - When U.S. tanks rumbled into this town on the Euphrates river, irregular Iraqi forces set up sniper nests up and down the main street, opening fire from doors, windows, market stalls and patches of open ground. A crimson sunset painted the street red and visibility fell to less than five meters (15 feet) as a swirling sand and dust storm kicked up when the guerrilla units attacked. U.S. officers said fighters in minivans, pick-up trucks and cars drove straight at the oncoming tanks. Others took to canoes, rowing down the river and trying to...