Update as of 7:34 a.m. EST: A senior official of Vietnam's Civil Aviation Administration, or CAA, reportedly announced that a 12-mile long oil slick spotted between Malaysia and Vietnam could be the first sign of the Malaysia Airline flight that went missing Saturday morning and is feared to have crashed into the South China Sea.

“An AN26 aircraft of the Vietnam Navy has discovered an oil slick about 20 kilometers in the search area, which is suspected of being a crashed Boeing aircraft -- we have announced that information to Singapore and Malaysia and we continue the search,” Lai Xuan Thanh, CAA's director, said, the New York Times reported.

Update as of 6:20 a.m. EST: Malaysia Airline, in a statement Saturday evening, announced that a search-and-rescue mission to locate missing Flight MH370 has not yet found evidence of any wreckage and that "the sea mission will continue while the air mission will recommence at daylight."

"An international search and rescue mission was mobilized this morning. At this stage, our search and rescue teams from Malaysia, Singapore and Vietnam have failed to find evidence of any wreckage," the statement said.

The latest statement also included the passenger manifest, which the airline had earlier declined to make public stating that it would only do so after all the family members of the missing passengers had been informed. According to the statement, there were 227 passengers on the flight, bound from Kuala Lumpur to Beijing, from 14 countries, alongwith 12 Malaysian crew members. The passengers also include one Chinese and one American infant.

Update as of 5:23 a.m. EST: Nearly 16 hours after the last known contact with Flight MH370, the governments of Malaysia, Vietnam, China, Singapore and the Philippines are assisting the airline in trying to locate the missing Boeing 777-200, which is suspected to have crashed into the South China Sea on Saturday.

As friends and relatives kept vigil while they await news of the plane, Malaysia Airline posted this message on its Twitter feed: "We understand everyone's concern on MH370 pax & crew. We're accelerating every effort with all relevant authorities to locate the aircraft."

A New York Times report, citing Fredrik Lindahl, CEO of Flightradar24, an online flight-tracking service, said that the aircraft's last recorded position was 93 miles northeast of Kuala Terengganu, a port on the northeasten coast of peninsular Malaysia. An earlier statement from the airline had noted the last known position "before it disappeared off the radar was 065515 North (longitude) and 1033443 East (latitude)."

Update as of 3:20 a.m. EST: The Philippines joined in a search for missing Malaysia Airlines Flight MH370 by sending three navy patrol boats and a surveillance plane to the South China Sea, The Nation, a local publication, reported. The Kuala Lumpur-based airline, which is tackling competition from a rash of discount airline traffic in Southeast Asia, has one of the best safety records in the region. 

Meanwhile, Malaysia Airlines released another statement at 3:30 a.m. EST, stating that it "is still unable to establish any contact or determine the whereabouts of flight MH370," adding: "So far, we have not received any emergency signals or distress messages from MH370. We are working with authorities and assure that all sources are deployed to assist with the search and rescue mission."

The statement also noted that the airline will dispatch a team of caregivers and volunteers to help family members of the missing plane's passengers. The plane, which is carrying mostly Chinese and Malaysian nationals (192 including one infant), also includes 3 U.S. nationals, including one infant.

Update as of 2:07 a.m. EST: China has dispatched two rescue ships to the South China Sea to look for survivors, CNN reported, citing state-run broadcaster CCTV, adding that relatives and friends of passengers gathered at a Beijing hotel as they awaited more details about the missing plane. There are reportedly 154 Chinese nationals on board MH370.

However, confusion surrounds the fate of the missing passenger jet with conflicting reports about the crash site with one online report, citing Reuters, stating that a Vietnamese admiral denied reports quoting him saying the plane crashed. According to a Reuters report, Malaysia's transport minister denied any crash scene was identified.

This is a developing story. Please check back for updates as more information becomes known.

The Vietnamese Navy said that Malaysia Airlines flight en route from the Malaysian capital, Kuala Lumpur, to Beijing, China, has crashed into the sea on Saturday. The news, reported by the website of Vietnam's biggest newspaper, Tuoi Tre, ends hours of speculation on the fate of flight MH370 after it had been reported missing and air traffic control authorities in several countries said they had lost contact with the aircraft. The Boeing 777 was carrying 239 people, including 227 passengers and 12 crew.   

"At the moment, we have no information of any wreckage," Ahmad Jauhari Yahya, chief executive of Malaysian Airlines, said in a press conference. "We do not know what happened to the plane," said another airline official at the press conference. 

The Malaysia Airlines site, which has not been updated yet to reflect confirmation of the crash, carried a statement that said the company is "currently working with international authorities on the search and rescue mission" and has no information on the location of the airliner. 

An earlier statement read, "we deeply regret that we have lost all contact with flight MH370, which departed Kuala Lumpur at 12:41 a.m. this morning bound for Beijing. The aircraft was scheduled to land at Beijing International Airport at 6:30 a.m. local Beijing time. Subang Air Traffic Control reported that it lost contact at 2:40 a.m. (local Malaysia time) today."

An official at the Civil Aviation Authority of Vietnam told Reuters the plane had failed to check in as scheduled while it was flying over the sea between Malaysia and Ho Chi Minh city. Chinese aviation authorities said the aircraft had not contacted them, either. "We are extremely worried," Chinese Foreign Minister Wang Yi told reporters in Beijing, as quoted by Reuters. 

Malaysia Airlines addressed earlier on its Facebook page unconfirmed reports that the plane landed in Nanming, China, saying "there has been speculation that the aircraft has landed at Nanming. We are working to verify the authenticity of the report."  However, a pilot contacted by the Sydney Morning Herald in Australia said it was unlikely that the plane had landed safely. "I think we can safely discount that," John Preston said.  

On Saturday morning local time in Kuala Lumpu, at the first of several press conferences the airline said it would hold every two hours, officials said the plane carried people of 14 nationalities, namely: China 152 people; Malaysia 38; Indonesia 12; Australia 7; U.S. 4; France 3; New Zealand 2; Ukraine 2; Canada 2; Russia, Italy, Taiwan, Netherlands, Austria all with 1.

They also said the plane was last contacted when it was flying at 35,000 feet and 472 knots, at normal crusing altitude and speed. The flight was commanded by a senior captain who had joined the company in 1981 and had more than 18,000 flight hours, making him a very experienced flyer.

According to a database maintained by Flight Global magazine, the plane had about 20,000 hours of accumulated flight time and had performed 3,020 takeoff and landing cycles. For a modern jetliner operated by a top international airline, those are numbers well within the service life of an airframe.

If there have been fatalities, an unfortunate virtual certainty in the case of a plane crashing into the sea from cruising altitude, this would be the second fatal accident to a Boeing 777 after an Asiana Airlines 777 series 200 model landed short of the runway in San Francisco in July 2013, killing three. Investigation of that accident is still pending, but most experts agree that pilot error probably played a large part.

Overall, this is the third accident to involve a 777. A British Airways jet, also a 200 series model, crashed on landing at London's Heathrow airport in 2008 due to loss of power after icing in one engine. No one was hurt.

Malaysia Airlines, with a fleet of 105 aircraft, is a large international carrier and a member of the Oneworld alliance, which includes American Airlines, the world's biggest airline, and British Airways.

It has a safety record comparable to major Western carriers. Its last fatal accident was the crash of a small Fokker 50 turboprop in 1995, with 34 killed.  

Several reports based on flight tracking sites indicated the aircraft that disappeared Saturday bore the Malaysian registration 9M-MRO. According to production lists published online by third parties not affiliated with the Boeing Co (NYSE:BA), that particular airplane was delivered new to Malaysia Airlines in May 2002 and was involved in a ground mishap in 2012. While taxiing at Shanghai's Pudong airport, its wingtip hit the tail of another aircraft. According to an independent accident-tracking site, the damage suffered by the Boeing 777 was "substantial."   

Boeing issued a statement early Saturday morning eastern US time, saying the company "offers its deepest concern to the families of those aboard missing Malaysian Airlines flight MH370" and announcing that it "is assembling a team to provide technical assistance to investigating authorities."