Iranian War Planes Attack U.S. Drone

Iran remained silent Friday amid accusations that two of its warplanes opened fire on a U.S. Air Force drone over international waters, an incident that further heightens tensions between the two countries over Tehran's nuclear program. A day after CNN first reported the incident -- later publicly confirmed by the Pentagon -- neither Tehran nor its state-run media said anything about the incident, which triggered a formal warning by the United States to Iran through diplomatic channels.