Sectarian violence has displaced more than 25,000 Iraqis since the Feb. 22 bombing of a Shiite Muslim shrine, a U.N.-affiliated agency said Tuesday, and shelters and tent cities are springing up across central and southern Iraq to house homeless Sunni and Shiite families. The flight is continuing, according to the International Organization for Migration, which works closely with the United Nations and other groups. The result has been a population exchange as Sunni and Shiite families flee mixed communities for the safety of areas where their own sects predominate. Full Story