KUALA LUMPUR—A Vietnamese search aircraft located fragments Sunday floating in waters off southern Vietnam that are suspected of coming from a Malaysia Airlines 3786.KU 0.00% jetliner that went missing a day earlier with 239 people on board. The fragments were believed to be a composite inner door and a piece of the tail, Vietnam's ministry of information and communication said in a posting on its website. They were located about 50 miles south-southwest of Tho Chu island. Officials released photograph of one fragment floating in the water. Malaysia Airlines said it had received no confirmation regarding the suspected debris. Flight...