A Malaysia Airlines flight carrying 227 passengers and 12 crew 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 Boeing 777-200ER flight from Kuala Lumpur to Beijing had crashed off south Vietnam, but Malaysia's transport minister later denied any crash scene had been identified.
''We are doing everything in our power to locate the plane. We are doing everything we can to ensure every possible angle has been addressed,'' Transport Minister Hishamuddin Hussein 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 777-200ER 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.
Two New Zealanders have been confirmed among the 239 people onboard the flight.
Flight MH370 departed Kuala Lumpur at 12.41am (05.41am NZT) and was expected to land in Beijing at 6.30am (11.30am NZT). Subang Air Traffic Control reported that it lost contact at 2.40am Malaysia time.
The flight was carrying a total number of 227 passengers - including two babies - and 12 crew members. The passengers were of 14 different nationalities with Chinese making up 152 of the persons on board.
As it became apparent this was not a routine plane delay, heart-wrenching scenes unfolded at the arrivals hall at Beijing's international airport terminal.
With the arrivals board still showing the Malaysian Airlines flight MH370 from Kuala Lumpur as delayed on Saturday morning, distraught family members and friends broke down as news filtered through that the flight had in fact gone missing hours earlier.
"They keep saying there's no information," Zhai Le told Fairfax Media, explaining through tears that she had a friend on board the flight.
One woman was seen crouched down on the floor sobbing, before a male companion and police led her away. Another man appeared shell-shocked as he explained he had been waiting to pick up his boss, a French national, when he heard the news.
Chang Ken Fei, a Malaysian waiting at Beijing airport for friends to arrive, said: " At first I thought the plane was just delayed as normal, so I came a bit later, I've just been waiting and waiting," he told Reuters.
Police and airport staff escorted relatives to the Beijing Lido Hotel to wait for news, even as flustered family members continued to arrive at the airport, desperate for information.
With 154 Chinese nationals on the Malaysian Airlines flight, the news has received blanket coverage in China, and Chinese foreign minister Wang Yi cut short a scheduled press briefing at the National People's Congress to attend to the fall-out.
"We are extremely worried," Wang said. "We are doing all we can to get details. The news is very disturbing."
China's state-run news agency Xinhua reported the plane was lost in airspace controlled by Vietnam, and did not make contact with Chinese air traffic controllers.
Chinese authorities dispatched two rescue boats two assist with the search and rescue operations and said there were no storms in the area of the South China Sea where the plane was flying across.
The airline, speaking several hours after the plane had been due to land in the Chinese capital, said it was still too early to say whether the aircraft had crashed.
It said there had been no distress signal and it cited early speculation that the plane may have landed in Nanming in southern China.
The airline confirmed the passenger manifest recorded two New Zealand passport holders. The airline is notifying next of kin in a sign it expects the worst.
Six Australians have also been confirmed on board. This corrects an earlier figure of seven Australians on board.
In New Zealand, a Ministry of Foreign Affairs and Trade spokeswoman said the High Commission in Kuala Lumpur was in contact with the airline seeking to confirm for certain whether New Zealanders were on board.
The Chinese news agency Xinhua reported the plane was lost in airspace controlled by Vietnam, and did not make contact with Chinese air traffic controllers. The plane was travelling at 35,000 feet when contact was lost.
Its pilots had made contact with air traffic control in the Vietnamese city of Ho Chi Minh.
On its website, Malaysia Airlines said the flight was piloted by Captain Zaharie Ahmad Shah, a Malaysian aged 53.
"He has a total flying hours of 18,365 hours. He joined Malaysia Airlines in 1981. First officer, Fariq Ab Hamid, a Malaysian, is aged 27. He has a total flying hours of 2,763 hours. He joined Malaysia Airlines in 2007."
There were no storms in the area of the South China Sea and the weather was generally fine with light clouds.
The aircraft had enough fuel to fly for seven hours, one hour more than the flight time to Beijing.
A flight-tracking website said communication was lost 20 minutes after departure from Kuala Lumpur.
- Flightradar24.com (@flightradar24) March 8, 2014
"It doesn't sound very good," retired American Airlines captain Jim Tilmon told CNN.
He said that the route was mostly overland, which meant that there would be plenty of radars and radios to contact the plane.
"I've been trying to come up with every scenario that I could just to explain this away, but I haven't been very successful."
He said the plane was "about as sophisticated as any commercial airplane could possibly be".
Malaysia Airlines Group Chief Executive Officer Ahmad Jauhari Yahya expressed his sadness over the event earlier: "We deeply regret that we have lost all contacts with flight MH370 which departed Kuala Lumpur at 12.41 am earlier this morning bound for Beijing.
"Our team is currently calling the next-of-kin of passengers and crew.
"Focus of the airline is to work with the emergency responders and authorities and mobilise its full support.
"Our thoughts and prayers are with all affected passengers and crew and their family members."
Malaysia Airlines denied reports circulating on the internet the plane had landed safely in Nanjing China.
"It's not true. We don't know where the plane is now," said Fuad Sharuji, from the the airline's operation control centre.
The pilots made no distress call. Fuad confirmed contact was lost two hours into the six hour flight.
Malaysia Airlines was ranked in last year's World Airline Awards as 14th in the world based on customer ratings, four places ahead of Air New Zealand. It has a six out of seven safety rating on airlineratings.com.
There have been two fatal incidents on Malaysia Airlines planes, with a total of 134 fatalities.
On December 4, 1977, a plane was hijacked and crashed killing all 100 on board, the deadliest crash of all time in Malaysia.
On September 15, 1995 a flight crashed during approach due to pilot error, killing 34.
The Boeing 777 is considered one of the world's safest aircraft.
Its first fatal accident was when Asiana Airlines Flight 214 crashed on final approach to San Francisco in July 2013, killing three and injuring 181 of the 307 people on board.
Safety experts said the design of the aircraft helped prevent a much worse disaster.
Malaysia Airlines said the public can call +60-378841234 for information about the flight.
-Fairfax Media and Reuters