Wednesday, April 16
(Undated) -- Officials say nearly 300 passengers are missing after many leaped from a sinking ferry in South Korea early today. A U.S. Navy ship and helicopters joined rescue crews in the frantic search for survivors. At least four people are known to be dead. It's not clear what caused the ferry to sink in apparently calm conditions. Many of the nearly 460 passengers on board were high school students on a field trip.