During a demonstration in Managua, Nicaragua, Viviana Reyes, left, holds a cross with a photo of her son, who was killed by Contra rebels. With her, Zeledonia Alvarado holds two crosses for her two daughters, who were kidnapped by the rebels. Another demonstration has been called for by Nicaragua's largest opposition organization to demand a "national salvation government" and to protest a recent crackdown by the leftist government. The demonstration would take place Sept. 4 in Managua's downtown Plaza of the Revolution. There was no immediate comment from the Sandinista government, but there is little chance it will grant the necessary permit. It rejected two other requests in the past month.