09:21 GMT - AFP IS CLOSING THIS LIVE REPORT on the Malaysia Airlines jet that has gone missing over Southeast Asia with 239 people aboard.
Vietnam authorities said contact with Flight MH370 was lost near its airspace, but its exact location and what happened to it remained a mystery 12 hours after it slipped off air-traffic control screens.
Malaysia Airlines said the plane, on an overnight flight from Kuala Lumpur to Beijing, relayed no distress signal, indications of rough weather, or other signs of trouble.
Meanwhile the search is continuing as relatives wait anxiously.
09:03 GMT - Singapore helps - Singapore's Air Force says on its Facebook page that it has dispatched a C130 plane to help in the search operations.
08:54 GMT - Facts on 777-200 - Some facts on the Boeing 777-200.
The model is the oldest in the Boeing 777 family and has a range of 5,240 nautical miles (9,700 kilometres), according to the Boeing website. Its typical cruising speed at 35,000 feet is Mach 0.84.
Boeing 777 family of long-range, wide body, twin-engined planes have a solid safety record and have been among the world's most widely-flown passenger jets since first entering service in 1995.
08:38 GMT - No confirmation - Malaysian Transport Minister Hishammuddin Hussein says he has not been able to confirm an earlier report by Vietnamese state media, quoting a naval official saying the plane had crashed off southern Vietnam.
"But since that information came from the Vietnamese navy, I have asked our navy to contact their counterparts immediately," he told reporters in Kuala Lumpur.
"At the moment we have no information of any wreckage at sea. I can confirm that we have not yet found the location of the plane."
Grief and prayers
08:21 GMT - Cameraman punched - For some the grief is too much.
Neil Connor in Beijing reports seeing a man who appeared to be in his sixties entering a room, wiping tears from his eyes with a handkerchief, and punching a cameraman in the face when he tried to film him as he walked by.
At the same time a security shouted "Don't you all have families."
08:18 GMT - A father mourns - Hamid Ramlan, a 56-year-old policeman living in the capital Kuala Lumpur, tells AFP that his daughter, 34, and son in law, 24, were on the flight.
"My wife is crying. Everyone is sad. My house has become a place of mourning. This is Allah's will. We have to accept it. But we will from tonight hold special prayers for Allah's help. I want to see my daughter and her husband who were on the flight to Beijing for a holiday," he says.
"There was no premonition that something bad will happen. I drove them to the airport. We hugged and my daughter was so happy to go on the trip. Being a policeman over 33 years, this is my worst day," he adds.
Some 10 people have gathered inside their small police apartment quarters to offer condolences with more expected to come.
08:11 GMT - Airport wait - At Kuala Lumpur airport an AFP photographer reports similar scenes to those in Beijing, with relatives, some in tears, coming and going from a specially designated waiting area at the airport. Most decline to speak to the media.
07:49 GMT - Foreign "guests" - Also at the hotel another women tells Neil she works for a "foreign trade company" and was waiting for four Australians, whom she described as "guests" of the company, without elaborating.
One women in her twenties entered the room frantically crying, ignoring questions from a large group of journalists who had crowded outside the door.
Security at times struggled to hold back a huge throng of reporters who made it difficult for the families to enter or exit the room.
07:46 GMT - My colleague Neil Connor at the Lido Hotel, near Beijing airport where relatives and friends of the passengers were taken, as spoken to some of the people there.
"They should have told us something before now," said one man at the hotel, who was in his thirties and from the northern Chinese city of Tianjin. The man, who was visibly distressed, did not say who was on the airplane that he came to meet.
Another man, who was also in his twenties, struggled to help someone who appeared to be his grieving mother into a quiet room, as journalists tried to interview her.
He then angrily said: "We haven't been told anything about this. They (Malaysia Airlines) are useless. I don't know why they haven't released any information."
07:33 GMT - China ships - China's State Oceanic Administration says it has ordered maritime patrol vessels conducting missions nearby to head to the area to join rescue efforts.
07:32 GMT - Figure change - The airline has tweaked it's nationality figures again. Indonesians down from 12 to 7. Now includes five Indians
07:19 GMT - As the location and fate of the plane continues to remain in doubt, authorities at Beijing have gathered the passengers' families at a nearby hotel.
Many of them were seen breaking down in tears as they arrived at the airport.
07:05 GMT - Safety - The Boeing 777 has a solid safety record, with only a handful of incidents since its introduction in the mid-1990s.
In July 2013, a Boeing 777-200 operated by South Korea's Asiana Airlines skidded off the runway upon landing at San Francisco's international airport after it clipped a seawall before touching down.
Three people died.
"We're closely monitoring reports on Malaysia flight MH370. Our thoughts are with everyone on board," Boeing said in a statement on its Twitter feed.
06:58 GMT - 'Delayed' - Screens at Beijing's airport first indicated the flight was "delayed", but later updated its status to "cancelled."
06:56 GMT - 'Very worried' - In Beijing, Chinese Foreign Minister Wang Yi as said the "news has made us all very worried."
"We hope every one of the passengers is safe. We are doing all we can to get more details."
06:48 GMT - Crew needed - Aviation analyst Gerry Soejatman explains that even modern planes still need the crew to make decisions.
"If the crew is not on the ball, they quickly lose control of the situation and themselves and end up in trouble.”
“Modern planes are safer, but you still need the crew to make the decisions. The technology is to ease their jobs, and not to replace them."
06:37 GMT - 12 hours - It is now nearly 12 hours since contact was lost at 2:40 am Malaysian time (1840 GMT Friday)
Search and rescue
06:26 GMT - Ships sent - Faridah Shuib, a spokeswoman for the Malaysian Maritime Enforcement Agency says Malaysian authorities have dispatched a plane, two helicopters and four vessels to search seas off its east coast in the South China Sea.
The Philippines says it is sending three navy patrol boats and a surveillance plane to help efforts.
06:24 GMT - No warning - The airline has said the plane relayed no distress signal or other indications of trouble.
06:12 GMT - Good record - Malaysia Airlines (MAS) has suffered few accidents in its history.
One of its jets crashed in 1977 in southern Malaysia, killing all 93 passengers and seven crew.
A smaller Twin Otter aircraft, operated by its unit MASwings, crashed upon landing in Malaysia's Sabah state on Borneo island last October, killing a co-pilot and a passenger.
06:09 GMT - Fuel - Aviation analyst Gerry Soejatman adds the aircraft would typically have been carrying two hours’ worth of fuel on top of the total fuel load needed for the trip from Kuala Lumpur to Beijing.
He said there was “nothing abnormal” about MAS’safety record.
“On the maintenance side there is nothing. Even on the rumour mill there is nothing drastic, of course in the workplace there are always problems. There is nothing that would jump out straight out of the page.”
06:04 GMT - "Golden window" - Indonesia-based independent aviation analyst Gerry Soejatman, speaking to my colleague Roberto Coloma from Jakarta says search and rescue efforts have to work within a “24-hour golden window.”
“You can’t assume that there are no survivors, and if there are any, it is absolutely crucial that they are picked up within a day, or the chances of survival drops significantly.”
“Airline pilots are not trained in crash landings in the sea, but they are taught the techniques. Both the pilots and the cabin crew are also taught the survival skills necessary in such situations.”
05:49 GMT - Search area - The important thing now for officials is to locate exactly where the plane may have gone down to narrow the search area.
The Vietnamese government on its website has already said the plane lost contact in Ca Mau province airspace before it had entered contact with Ho Chi Minh City air traffic control.
A report by China's Xinhua news agency quoted Chinese aviation authorities as saying the plane did not enter China's air traffic control sphere, and a spokeswoman with a Thai agency that monitors the country's airspace told AFP the plane also did not cross over Thailand.
05:42 GMT - Contact site - In the statement the airline also gives a site for updates, but an attempt by AFP to visit received an error message.
05:37 GMT - Contact number - The airline statement also gives a number for the public to contact - +603 7884 1234
05:25 GMT - Airline CEO's statement -
Malaysian Airlines is running a statement given by Group CEO Ahmad Jauhari Yahya on its Facebook site, in which he expresses his sadness and confirms Flight MH370 "lost contact with Subang Air Traffic Control at 2.40am, today."
He adds there has been "speculation" the plan had landed at Nanming, in China. "We are working to verify the authenticity of the report and others."
The statement also gives a breakdown of the 239 passengers and crew – comprising 227 passengers (including 2 infants), 12 crew members.
The passengers were of 14 different nationalities:
China – 152 plus 1 infant
Malaysia - 38
Indonesia - 12
Australia - 7
France - 3
US – 3 plus 1 infant
New Zealand - 2
together with one each from Ukraine, Canada, Russia,Italy, Taiwan, Netherlands and Austria.
"Our focus now is to work with the emergency responders and authorities and mobilize its full support," he said, adding "our thoughts and prayers are with all affected passengers and crew and their family members."
05:15 GMT - Sympathy - My colleague Julia Zappei in Kuala Lumpur says the Malaysian Prime Minister Najib Razak has tweeted " My thoughts and prayers are with the family members of flight #MH370. I've asked all measures possible to be taken."
05:13 GMT - Never appeared - A Vietnam government statement on its official website quoting a ministry of defence official says the plane was meant to transfer to Ho Chi Minh City air traffic control at 1722 GMT but never appeared.
The statement goes on to say that Vietnam's Ministry of Defence has launched rescue efforts to find the plane, working in coordination with Malaysian and Chinese officials.
05:10 GMT - No news - Reporters at the Kuala Lumpur International Airport are being barred from entering a specially designated waiting area for relatives of those on the flight.
Looking somber and distraught relatives are trickling into the airport escorted by authorities.
"They gave us no information so far," said one man, whose niece and her husband were on the flight to go on a one-week holiday in China.
05:03 GMT - WELCOME TO AFP'S LIVE REPORT on a Malaysia Airlines flight carrying 239 people from Kuala Lumpur to Beijing which went missing early Saturday.
The airline said flight MH370 disappeared at 2:40 am local time (1840 GMT Friday), about two hours after leaving Kuala Lumpur International Airport. It had been due to arrive in Beijing at 6:30 am local time (2230 GMT Friday).
A statement posted on the official Vietnamese government website said the flight disappeared in Vietnamese airspace.