President Xi Jinping on Saturday urged emergency measures over the missing Malaysian flight that went missing en route to Beijing with 239 crew and passengers, more than 150 of them Chinese.

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Xi ordered the Ministry of Foreign Affairs as well as Chinese embassies and consulates to strengthen contact with relevant countries and pay close attention to the search and rescue work for the plane, which lost contact with traffic controllers and vanished at 1:20am on Saturday.

All-out efforts must be made for any emergency treatment necessary in the aftermath of the incident, Xi said in his remarks about the incident.

The Ministry of Transportation and the Civil Aviation Administration must launch emergency measures immediately and enhance security checks to ensure the "absolute safety" of China's civil aviation operations, according to the president.

Ships, Aircraft on Standby

Eight ships belonging to the Nanhai Rescue Bureau and the Hainan Maritime Safety Administration are on standby to locate the missing plane and rescue any survivors. An aircraft fleet is reportedly also ready to take off.

Yang Chuantang, Chinese Minister of Transport, announced the launch of the highest-degree of the national emergency response mechanism.

The ministry is closely observing the incident and actively coordinating with domestic authorities as well as maritime rescue authorities and civil aviation administrations in Malaysia and Vietnam.

Malaysia Airlines denies crash

The Beijing-bound flight MH370, a Boeing 777-200, departed Malaysia's capital of Kuala Lumpur at 12:42am Beijing time on Saturday, and was expected to land in Beijing at 6:30am the same day.

The plane went missing over the South China Sea, presumed crashed, as ships from countries closest to its flight path scoured a large search area for any wreckage.

Vietnamese state media, quoting a senior naval official, had reported that the flight had crashed off southern Vietnam, but Malaysia's transport minister later denied that any crash scene had been identified.

"We are doing everything in our power to locate the plane. And doing everything we can to ensure every possible angle has been addressed," Hishamuddin Hussein, Malaysia’s Transport Minister, told reporters near the Kuala Lumpur International Airport.

"We are looking for accurate information from the Malaysian military. They are waiting for information from the Vietnamese side," he said.

Vietnam's state-run Tuoi Tre news also quoted Admiral Ngo Van Phat as qualifying his earlier remarks about a crash site having been identified, saying he had been referring to a presumed crash site beneath the plane's flight path using information supplied by Malaysia.

A crash, if confirmed, would mark the US-built Boeing 777-200 airliner's deadliest incident since entering service 19 years ago.

The plane disappeared without giving a distress signal - a chilling echo of an Air France flight that crashed into the South Atlantic on June 1, 2009, killing all 228 people on board. It vanished for hours without issuing a distress call.

Vanished after 35,000ft

The flight MH370 last had contact with air traffic controllers 120 nautical miles off the east coast of the Malaysian town of Kota Bharu, Malaysia Airlines chief executive Ahmad Jauhari Yahya said in a statement read to an earlier news conference in Kuala Lumpur.

Flight tracking website flightaware.com showed the plane 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.

Malaysia and Vietnam were conducting a joint search and rescue operation, he said, but gave no details.

"We are extremely worried," Chinese Foreign Minister Wang Yi told reporters in Beijing on Saturday. "The news is very disturbing. We hope everyone on the plane is safe."

No trace has been found of the plane now more than eight hours after it was due to land in the Chinese capital.

"We deeply regret that we have lost all contacts with flight MH370," Jauhari said.

If it is confirmed that the plane has crashed, the loss would mark the second fatal accident involving a Boeing 777 in less than a year. An Asiana Airlines Boeing 777 crash-landed in San Francisco in July 2013, killing three passengers and injuring more than 180.

Boeing said it was aware of reports that the Malaysia Airlines plane was missing and was monitoring the situation but had no further comment.

An official at the Civil Aviation Authority 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.

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