BEIJING — A Malaysia Airlines flight carrying 239 people from Kuala Lumpur to Beijing remained missing hours after it lost contact with air traffic controllers Saturday, and a search-and-rescue effort was under way, officials said.

Flight MH370, with 227 passengers and 12 crew members aboard, was scheduled to land in the Chinese capital at 6:30 a.m. but did not arrive. It departed from the Malaysian capital at 12:41 a.m. Saturday and lost contact with Malaysian air traffic controllers about two hours later, the airline said.

China sent two ships for search-and-rescue operations in the South China Sea in connection with the missing flight, CCTV reported.

“We are working with authorities who have activated their Search and Rescue team to locate the aircraft,” the airline said in a statement on its web site. “Our team is currently calling the next-of-kin of passengers and crew.”

The airline identified the pilot of the Boeing 777-200 as Capt. Zaharie Ahmad Shah, 53, who joined airline in 1981. The first officer was identified as Fariq Ab.Hamid, 27, who joined the airline in 2007.

Officials said the flight included passengers from China, Malaysia, Indonesia, Australia, France, the United States, New Zealand, Ukraine, Canada, Russia, Italy, Taiwan, the Netherlands and Austria. Most passengers came from China, 153, and Malaysia, 38.

Three passengers carrying U.S. passports were identified as Phillip Tallmadge Wood, 50, Nicole Meng, 3, and Leo Meng, 1.

The flight apparently disappeared before entering Chinese airspace. The New China News Agency said the pilots had not been in touch with Chinese air traffic control.

The Civil Aviation Administration of Vietnam said the plane had failed to check in as scheduled while it was flying over the sea between Malaysia and Ho Chi Minh City, Vietnam.

Fuad Sharuji, vice president of operations control for the airline, told CNN that the plane was flying at 35,000 feet and that no problems had been reported before contact was lost.

The “focus of the airline is to work with the emergency responders and authorities and mobilize its full support,” the airline said. “Our thoughts and prayers are with all affected passengers and crew and their family members.”

“We’re closely monitoring reports on Malaysia flight MH370,” Chicago-based Boeing said on its Twitter feed. “Our thoughts are with everyone on board.”

As of 11 a.m. the flight status board at Beijing Capital International Airport still listed the flight as “delayed,” and family members were being directed to the nearby Lido Hotel.

“My son! My son!” one person wailed later from inside the room at the hotel complex where families were sequestered. “What am I going to do?”

Zhai Le was waiting for her friends, a couple who were on their way back to the Chinese capital on the flight, the Associated Press reported. She said she was very concerned because she hadn’t been able to reach them.