US investigators suspect a missing Malaysian jetliner flew on for four hours once it lost contact with air traffic controllers, according to the Wall St Journal.
The suspicion is based on data from the plane's engines that are automatically downloaded and transmitted to the ground as part of routine maintenance programs.
The report raises questions as to why the Boeing 777 was flying like that, and if anyone was in control during that time.
The plane's last known confirmed position was roughly halfway between Malaysia and Vietnam.
Malaysian authorities have since said they tracked what could have been the plane changing course and heading west.
Investigators have not ruled out any possible cause to explain the disappearance of the plane and the 239 people on board.
No debris at satellite spot
No signs of the missing Malaysian jetliner have been found at a spot where Chinese satellite images showed what might be plane debris, Malaysia's civil aviation chief said Thursday, deflating the latest lead in the five-day hunt.
"There is nothing. We went there, there is nothing," Azharuddin Abdul Rahman told reporters in Kuala Lumpur.
Vietnamese officials previously said the area had been "searched thoroughly" in recent days.
The hunt for the Boeing 777 has been punctuated by false leads since it disappeared with 239 people aboard just hours after leaving Kuala Lumpur for Beijing early Saturday. The plane was heading northeast over the South China Sea when it disappeared, but authorities believe it may have turned back and headed into the upper reaches of the Strait of Malacca or beyond.
The location where Chinese images showed possible debris is not far from where the last confirmed position of the plane was between Malaysia and Vietnam. The images and coordinates were posted on the website of China's State Administration of Science, Technology and Industry for National Defense.
A Xinhua report said the images from around 11 a.m. on Sunday appear to show "three suspected floating objects" of varying sizes in a 20-kilometer radius, the largest about 24-by-22 meters (79-by-72 feet) off the southern tip of Vietnam.
Pham Quy Tieu, deputy transport minister, told The Associated Press that the area had been "searched thoroughly" by forces from other countries over the past few days. Doan Huu Gia, chief of air search and rescue coordination center, said Malaysian and Singaporean aircraft were scheduled to visit the area again Thursday.
Li Jiaxiang, chief of the Civil Aviation Administration of China, said later China had yet to confirm any link between the suspected floating objects and the plane.
Malaysia has come under some criticism for its handling of the search, which currently covers 35,800 square miles (92,600 square kilometers) and involves 12 nations.
'We're in the dark'
Malaysian political and military leaders fronted a news conference in Kuala Lumpur late last night (NZT) and admitted that, five days into the search for Flight 370, they still had no idea what's happened to the jet or where it might be.
In scenes that often descended into a shouting match with the world's media, they said that 42 ships and 39 aircraft from 12 countries were now searching for the Boeing 777 over an area of 27,000 square nautical miles.
They admitted that once contact was lost with the Malaysia Airlines plane, no radar system tracked it in real time. Indications that it changed direction and flew over the Straits of Malacca came from analysis of recorded data.
The Acting Minister of Transport, Hishamuddin Tun Hussein, was put on the defensive when an exasperated Malaysian reporter asked why the facts kept changing, and why the officials were so "stingy" with information and said it wasn't a "good look" for the country.
Others also accused the panel of hiding information and called for raw data to be released.
The news conference started more than two hours late. In a bizarre scene that seemed to sum up Chinese frustrations at pace of Malaysian reaction to the disappearance, the Chinese Ambassador to KL — in the absence of any Malaysian officials — began giving an interview at the front of the assembled journalists, until an official pointed out the conference was for interviewing Malaysian leaders.
Earlier, families and friends looking for a breakthrough in the missing Malaysia Airlines jetliner inquiry said the wait had been "frustrating" and "infuriating". The family of New Zealander Ximin Wang were among those who had taken up the airline's offer to wait in Kuala Lumpur for updates on the search for loved ones.
Most were getting restless, angry and frustrated.
A relative of one of the passengers, who declined to be named, said she had decided to travel to KL because she was "going crazy" about the lack of updates from the airline in Beijing.
Six Chinese nationals who arrived from Beijing on Tuesday began screaming at the media as they were escorted from their rooms to lunch.
Some, who have turned up at the Kuala Lumpur International Airport daily, are calling for officials to "come clean and be upfront".
"How can they take (five) days to find out that the plane had turned around when the information came from our own Malaysian military?" said Mohammed Johari, who lost an uncle on the flight.
"What else are they not saying? It is frustrating and infuriating."
Flight 370 disappeared from radar on Saturday with 239 people on board while flying from Kuala Lumpur to Beijing.
Updates were two hourly when the flight first went missing, but it was down to just the single press conference yesterday.
Airline shocked by pilot's party pics
A woman photographed in a Malaysia Airlines cockpit with one of the pilots from the company's missing aircraft says she and a friend were picked out of the boarding queue.
The airline said it was "shocked" by pictures of First Officer Fariq Abdul Hamid posing with two South Africans who said he smoked on the flight deck and allowed them to stay during take-off and landing, against airline rules.
Malaysia Airlines said it was "taking very seriously" an account from Jonti Roos, a former passenger who said Mr Hamid invited her and a friend on to the flight deck of another Malaysia Airlines aircraft, flying from Phuket, Thailand to Kuala Lumpur in 2011.
She said he had spent much of the journey smoking and chatting to his guests.
Miss Roos said that she and Jaan Maree were picked out of the boarding queue to join the pilots for the one-hour flight, and sat in jump seats in the cockpit during take-off and landing, against airline regulations.
She told Channel 9 television in Australia: "Throughout the whole flight they were talking to us, they were actually smoking throughout the flight, which I don't think they're allowed to be doing and they were taking photos with us in the cockpit while they were flying the plane."
She claimed that for much of the trip the pilots were not even facing the front of the plane.
Miss Roos said while the pilots were "possibly a little bit sleazy" and invited the women to stay with them in Kuala Lumpur, she felt they were in control of the aircraft.
- nzherald.co.nz, AFP, AP