China is very worried over a Beijing-bound plane that has lost contact with air traffic control, Foreign Minister Wang Yi said Saturday.

"The news is very disturbing. We hope everyone on the plane is safe," said Wang.

He made the remarks at the beginning of a press conference on the sidelines of the annual session of the National People's Congress, China's top legislature.

Wang said that China's Foreign Ministry and the related departments had activated an emergency response mechanism.

"As soon as we have any more information, we will give it to you immediately," he told reporters.

The country has dispatched two maritime rescue ships to the South China Sea to help in rescue work for the missing aircraft.

The Malaysian passenger plane carrying 239 people has lost contact with air traffic control after leaving Malaysia's capital Kuala Lumpur, the carrier said Saturday.

According to the airlines, a total of 154 Chinese nationals were onboard the plane, including one infant and one from Taiwan.

The Boeing B777-200 aircraft departed Kuala Lumpur at 00:41 a.m. Saturday, and was expected to land in Beijing at 6:30 a.m.

It lost communication and radar signal two hours into the flight over Vietnam at 1:20 a.m.

According to China's Civil Aviation Administration (CAAC), the flight hasn't contacted Chinese air traffic management department or entered China's air traffic control area.

Malaysia Airlines said it was working with the authorities who have dispatched search and rescue team to locate the plane.

Vietnamese media had reported earlier that signal of the missing plane had been detected at some 120 nautical miles southwest of Vietnam's southernmost Ca Mau province. Xinhua could not verify the report at the moment.

In Beijing, relatives and friends of passengers onboard the flight are waiting anxiously for news on the plane.

Chuang Ken Fei, a Malaysian, has been waiting for his two friends in the Terminal 3 of Beijing Capital International Airport for over 3 hours.

"Staff at the airport told me the flight did not take off, but I can see from my mobile application that the aircraft was in the air," Chuang said.

The Beijing Capital International Airport has formed an emergency group to deal with the incident.