Egypt said Wednesday it had found an arms-smuggling tunnel under the Gaza border, and Palestinians crossing the frontier were warned to return by sunset when passport controls will be reimposed. Egyptian border guards discovered the tunnel in the al-Duhniya area, 2 1/2 miles south of the Rafah crossing point, on Tuesday evening, a security official said. The tunnel contained 38 firearms and three rocket-propelled grenades, the official added, speaking on condition of anonymity because he was not authorized to speak to the press.Full Story