KUALA LUMPUR, Malaysia — Malaysia Airlines announced this morning that it had lost contact with one of its flights, which was carrying 239 people to Beijing from Kuala Lumpur.
The airline said it had activated a search-and-rescue team.
The Boeing 777-200 operating as Flight MH370 took off at 12:41 a.m. local time. (Kuala Lumpur is 13 hours ahead of Eastern Standard Time.) Air traffic control in Subang, a suburb of Kuala Lumpur, lost contact with the plane almost two hours later.
The airline issued its statement at 7:24 a.m. after the plane failed to arrive in Beijing; it had been scheduled to land at 6:30 a.m.
Malaysia Airlines said the flight had 227 passengers, including two infants, and a crew of 12. Airline staff members have begun contacting the families of passengers and crew.
"Our thoughts and prayers are with all affected passengers and crew and their family members," the airline's statement said.
Malaysia Airlines said more than 150 Chinese and four Americans were on board.
Chinese officials expressed concern.
"We are extremely worried upon hearing this news," Qin Gang, the spokesman for the Chinese Foreign Ministry, said in a statement. "We are currently in contact with relevant parties and are doing what we can to understand and confirm relevant circumstances."
He added that the Foreign Ministry, the Chinese Embassy in Malaysia and the Chinese Embassy in Vietnam had begun emergency procedures.
China deployed two rescue ships to the South China Sea to search for the plane, CNN reported, citing state-run broadcaster China Central Television.
If the flight were traveling in a straight line, it would have been traveling north up the entire length of Vietnam and Vietnam's coastal waters. There was no immediate comment from Vietnamese authorities.
However, Vietnamese website VN Express said a Vietnamese search and rescue official reported that signals from the plane were detected about 140 miles southwest of Vietnam's southernmost Ca Mau province.
Chinese air traffic control authorities said the plane had not entered airspace that they control or established communications with Chinese air traffic control, according to China Central Television.
In the terminal at Beijing International Airport, where Flight MH370 had been due to arrive, a woman burst into tears while on a telephone.
Liu Meng, 26, said he had been at the airport since shortly before the flight's scheduled arrival time, waiting for his boss to return from a business trip. The boss' relatives had been calling Liu with questions, and, he said, he had nothing to tell them.
A Malaysian man who gave only his surname, Zhang, said that he had been waiting at the airport for two Malaysian friends on the flight but that the airport authorities had told him only that the flight had been delayed; he had learned of the aircraft's disappearance from reading about it on the Internet.
There have been two previous crashes of Boeing 777s. Last July 6, an Asiana plane came in too slow and at too low an altitude and crash-landed at San Francisco International Airport. Three Chinese teenage girls were killed, and several others suffered serious permanent injuries. So far it does not appear that there was a mechanical problem with that aircraft.
Malaysia Airlines CEO Ahmad Jauhari Yahya said the 53-year-old pilot, Zaharie Ahmad Shah, has more than 18,000 flying hours. The first officer, 27-year-old Fariq Hamid, has about 2,800 hours of experience.
Malaysia Airlines' last fatal crash was in 1995 near the Malaysian city of Tawau, killing 34.