North Korea Submarine Missing, US Says: Report

North Korea lost contact with one of its submarines earlier this week, three U.S. officials familiar with the matter told CNN Friday. The U.S. is unsure whether the missing vessel is adrift at sea or has sunk, officials said. The U.S. military had been watching the submarine operate off North Korea's east coast when the vessel stopped. For days, the U.S. military has been secretly watching the North Korean navy search for the submarine, CNN reported.