Iraqi troops shoot at fleeing civilians By Sudarsan RaghavanKnight Ridder NewspapersPublished Monday, March 31, 2003 AZ ZUBAYR BRIDGE, Iraq -- Iraqi troops fired machine guns and artillery shells at several hundred families fleeing Basra on Sunday, triggering a shootout with British soldiers that pinned down terrified refugees in the cross-fire. Mothers in black Islamic garments clutched crying babies to their chests. Young men tightly held the hands of their grandmothers. And an old, sun-weathered man with a cane briefly looked to the heavens and yelled, ''Allah. God help me.'' British forces on the outskirts of Basra are facing an Iraqi...