Communications satellites picked up a faint 'electronic ping' from the missing Malaysian aircraft after contact was lost according to a source close to the investigation.
The signal was an indication the aircraft's troubleshooting systems were ready to communicate with satellites if required, but no data was sent because Malaysia Airlines had not subscribed to the full troubleshooting service, the source said.
International airlines use a reporting system which collects technical data during each flight so that engineers can identify problems. These reports are broadcast to engineers via VHF radio or satellite during the flight.
If the plane had disintegrated during flight or had suffered some other catastrophic failure, all signals - the pings to the satellite, the data messages and the transponder - would be expected to stop at the same time.
However, a US official said the signal was sent to the satellite for around four hours after the last verbal communication with the flight raising the possibility it flew on for hundreds of miles more.
News of the signal emerged as the White House announced a new search area may be opened in the Indian Ocean.
"It's my understanding that based on some new information that's not necessarily conclusive - but new information - an additional search area may be opened in the Indian Ocean," White House spokesman Jay Carney said.
"And we are consulting with international partners about the appropriate assets to deploy."
Two sources familiar with the investigation confirmed Boeing and Rolls-Royce did not receive any maintenance data after the pilots last made contact. Only one engine maintenance update was received during the normal phase of flight.
Despite an extensive search, no trace has been found of the missing plane since it disappeared six days ago and aviation experts have so far failed to locate the aircraft's black box recorder.
Malaysia's acting Transport Minister Hishammuddin Hussein: "MH370 went completely silent over the open ocean.
"This is a crisis situation. It is a very complex operation, and it is not obviously easy. We are devoting all our energies to the task at hand.
Malaysian air traffic control last spoke with flight MH370's pilots as the plane left their zone and moved into Vietnamese air space. Vietnamese official have said they never heard from the aircraft.
Malaysian Airlines has confirmed the missing flight had an Aircraft Communications Addressing and Reporting System (ACARS) on board. But the source claims no mechanical data was sent.
A statement released by the airline said that "All Malaysia Airlines aircraft are equipped with ... ACARS which transmits data automatically. Nevertheless, there were no distress calls and no information was relayed".
David Gallo, one of the world's most accomplished scientists in his field helped locate the black box data recorders of Air France flight 447 in the South Atlantic in 2011, two years after the plane crashed.
On the disappearance of the Malaysian Airlines passenger jet, he said: "This has rapidly become one of the great mysteries of all time in terms of loss of an aeroplane or ship at sea."