New reports claim Malaysia Airlines plane may have been flying for more than five hours after it disappeared.
According to a BBC report, it is believed the plane was sending automated signals to a satellite system long after radar contact was lost.
This would mean flight MH370 could have flown more than 1,000 miles beyond its last confirmed position.
On Friday, US surveillance teams were sent to the Indian Ocean, much further west than the initial searches
The Indian navy has also been asked to search an area in the Bay of Bengal off India’s Chennai coast, Malaysian authorities said on Friday.
Flight MH370 vanished last Saturday with 239 people on board.
The plane – which was supposed to be flying to Beijing from Kuala Lumpur – last made contact with air traffic control over the South China Sea to the east of Malaysia.
However, the BBC understands that a satellite system operated by London-based telecommunications company Inmarsat received an automated signal from flight MH370 at least five hours after the plane was reported lost.
The signal could only have been sent if the plane was intact and powered, and may explain why search teams have moved to the Indian Ocean.
Earlier, US media outlets also quoted unnamed officials as saying that the Boeing 777 was “pinging” satellites for hours after its last contact with air traffic controllers.
White House spokesman Jay Carney has confirmed that US teams were shifting their focus to the Indian Ocean because of “new information”, but gave no further details.
Malaysia has not yet commented on the latest claims.
The US – one of a number of countries helping to search for the plane – has sent a navy destroyer and a sophisticated surveillance aircraft to the Indian Ocean.
The Indian navy, air force and coast guard are also now involved after a request from the Malaysian government.
Indian naval spokesman DK Sharma said on Friday that six ships and five aircraft were scouring the Andaman Sea.
Malaysian authorities later said that India’s Eastern Naval Command was to search an area of sea 3,500 sq miles off the Chennai coast.
China said on Friday it was sending a patrol ship to the Malacca Strait, west of Malaysia, after a fruitless search in the Gulf in Thailand.
The official Xinhua news agency said experts and officials had met on Friday and “analyzed new information”, but did not give details.
Some 153 of the passengers on board the plane were Chinese, and Beijing has been pressing Malaysia to intensify its search.
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