Investigators say an oil slick in the South China Sea is not from the missing Malaysian Airlines flight. Malaysia is being asked to step up search efforts for the plane which has been missing for nearly three days now.
The Boeing 777 disappeared off the radar mid-flight between Kuala Lumpur and Beijing with 239 people on board. Numerous lines of inquiry are being followed, including terrorism and hijacking.
Investigators say a yellow object seen floating in the sea is not a life raft from the Malaysia Airlines plane that disappeared.
The reported sighting, made by the crew of a Vietnamese jet around 90 miles south-west of Tho Chu island, was another false alert for the teams of rescuers searching for flight MH370.
Samples of oil taken from a slick in the South China Sea, which it was hoped would provide answers for anxious relatives of the plane's passengers and crew, are also reportedly not from the aircraft.
The oil was used in shipping, rather than aviation, a spokeswoman for the Malaysian Maritime Enforcement Agency told the AFP news agency.
The route of the missing airliner
Authorities have said they are "puzzled" by the plane's "unprecedented" disappearance mid-flight between Kuala Lumpur and Beijing. Security services are investigating whether the Boeing 777-200 was hijacked or destroyed in a terror attack.
Earlier reports of debris spotted in the South China Sea, including an aircraft door, have not been confirmed, while a possible sighting of a section of the plane's tail has been ruled out.
At least two passengers boarded the flight using stolen passports and additional "suspect" documents are being investigated by Interpol.
The men using the false passports - one issued in Italy and the other in Austria - bought their tickets together and were due to fly to Europe after landing in Beijing.
Malaysian police chief Khalid Abu Bakar said one of the mystery passengers had been identified as a non-resident of the country using CCTV footage from Kuala Lumpur airport.
Officials are discussing whether images of the mystery passengers should be made public as part of an appeal for information.
Initial investigations suggest the plane disintegrated at about 35,000 feet, according to the Reuters news agency.
Had the plane plunged into the sea and broken up on impact, search teams would have expected to find a concentrated pattern of debris, a source involved in the probe said.
The search, which involves teams from 10 countries, has been widened after radar suggested the aircraft may have turned back before it vanished.
Relatives of those on the flight are enduring an agonising wait for information and anger is growing in China about the lack of progress with the investigation.
Nearly two-thirds of the passengers were Chinese and if the loss of the plane is confirmed, it would be the country's second-worst air disaster.
Journalist Clifford Coonan is in China. He told the Pat Kenny Show here on Newstalk that investigators are puzzled over the complete disappearance of the aircraft.
Todd Curtis is a former safety engineer at Boeing.
He says a beacon that can transmit the location of the plane will not function if it is underwater, but there is another way the aircraft can tell investigators its whereabouts.
