More than 200 people are feared to have been killed after a Malaysia Airlines flight went missing.
The plane, carrying 227 passengers and 12 crew, was travelling between Kuala Lumpur and Beijing.
Chinese state news agency Xinhua reported radar contact was lost around two hours into flight while it was in Vietnamese airspace.
Officials say most of the people on board are Chinese and a search and rescue operation is underway.
If the plane is found to have crashed, the loss would mark the second fatal accident involving a Boeing 777 in less than a year, after an unblemished safety record since the jet entered service in 1995.