HANOI - The last contact made by the ill-fated Malaysia Airlines flight was over the South China Sea between Kuala Lumpur and Ho Chi Minh city, officials said.
Flight MH370, operating a Boeing 777-200ER aircraft, last had contact with air traffic controllers 120 nautical miles off the east coast of the Malaysian town of Kota Baru, Malaysia Airlines chief executive Ahmad Jauhari Yahya said in a statement read to the news conference in Kuala Lumpur.
The flight left Kuala Lumpur at 12.21am on Saturday.
It was due to land in the Chinese capital at 6.30am on the same day.
An official at the Civil Aviation Authority of Vietnam (CAAV) said the plane had failed to check in as scheduled while it was flying over the sea between Malaysia and Ho Chi Minh City.
The Boeing 777-200ER has a range of 14,305km.
While the fate of flight MH370 remains unclear, flight tracking website flightaware.com showed that it flew northeast over Malaysia after takeoff and climbed to an altitude of 35,000 feet.
The flight vanished from the website's tracking records a minute later while it was still climbing.
Chinese and Vietnamese media reported that an unspecified signal had been picked up from the plane near Cape Ca Mau, 250 km southwest of Ho Chi Minh city, but a Vietnamese maritime search and rescue official said that was not true.
"We have been seeking but no signal from the plane yet," Pham Hien, director of a Vietnam maritime search and rescue coordination center in Vung Tau, said.
China's official Xinhua news agency also quoted the Civil Aviation Administration of China (CAAC) as saying the flight lost contact while flying through Vietnamese airspace.
China's aviation regulators said they had not received any signals from the plane and that there had been no reports of any aircraft cashing in Chinese waters.