Malaysia Airlines said a flight carrying 239 people from Kuala Lumpur to Beijing went missing early Saturday, and the airline was notifying next of kin in a sign it feared the worst.
The airline said flight MH370 disappeared at 2:40 am local time (1840 GMT Friday), about two hours after leaving Kuala Lumpur International Airport. It had been due to arrive in Beijing at 6:30 am local time (2230 GMT Friday).
A statement posted on the official Vietnamese government website said the flight disappeared in Vietnamese airspace.
'The plane lost contact in Ca Mau province airspace before it had entered contact with Ho Chi Minh City air traffic control,' it said.
The plane was meant to transfer to Ho Chi Minh City air traffic control at 1722 GMT but never appeared, the statement said, citing a senior Ministry of Defence official.
Vietnam's Ministry of Defence has launched rescue efforts to find the plane, working in coordination with Malaysian and Chinese officials, the statement added.
The Boeing 777-200 was carrying 227 passengers, including two infants, from 13 different nationalities, and 12 crew members.
China's state television said 158 of the passengers were Chinese. Some 160 Chinese had been due to be on the flight but two missed it, according to Xinhua, quoting China's Civil Aviation Administration.
'We deeply regret that we have lost all contacts with flight MH370 which departed Kuala Lumpur.