Greece's two largest labor unions say they will push ahead with demonstrations in riot-ravaged Athens as part of a 24-hour strike Wednesday to protest the government's economic policies. On Tuesday, the unions flouted an appeal from Prime Minister Costas Karamanlis to refrain from fueling four days of violence triggered by the fatal shooting of a teenager. A police officer is charged with the killing. Greece's transport will grind to a halt Wednesday as flights and ferry links will be cut and train service severely limited. Umbrella unions GSEE and ADEDY together represent some 2.5 million workers, about half of Greece's total work force. They demand more state social spending, as well as salary and pension increases.