Malaysia Airlines on Saturday announced that it has lost contact with a plane travelling from Kuala Lumpur to Beijing, with 239 people on board.
The airline said in a statement that flight MH370 disappeared at 02:40 local time on Saturday (18:40 GMT on Friday).
It was expected to land in Beijing at 06:30 (22:30 GMT).
“Malaysia Airlines is currently working with the authorities who have activated their search and rescue team to locate the aircraft,” the carrier said.
“Our team is currently calling the next-of-kin of passengers and crew.”
The Boeing B777-200 aircraft was carrying 227 passengers, including two children, and 12 crew members.
In a brief press conference on Saturday, Malaysia Airlines chief executive Ahmad Jauhari Yahya said the company was still working to establish the location of the plane – including looking into reports that the aircraft has landed at Nanming in southern China.
He said the company was “deeply saddened” at the situation and that it would provide regular updates.
He also stated that the passengers were of 14 different nationalities.
Among them were 152 Chinese nationals, 38 Malaysians, 12 people from Indonesia and seven from Australia.
The pilot was Capt Zaharie Ahmad Shah, 53, who joined Malaysia Airlines in 1981, Mr Yahya said.
The flight went missing two hours after taking off from Kuala Lumpur.
China’s Xinhua state news agency said it was lost in airspace controlled by Vietnam.
The aircraft did not enter airspace controlled by China and did not make contact with Chinese controllers, the agency added.