A multinational fleet of planes and ships raced Friday to a fresh search zone after a "credible new lead" that Malaysia Airlines Flight MH370 was flying faster than first thought before it plunged into the remote Indian Ocean.
Ten aircraft from six countries -- Australia, China, Japan, New Zealand, South Korea and the United States -- diverted to an area 1,100 kilometres (685 miles) northeast of where they have been looking for a week, far off western Australia.
Five Chinese ships and an Australian naval vessel were also steaming to the new zone of interest after the weather cleared following the suspension of the air search Thursday due to thunderstorms and high winds, the Australian Maritime Safety Authority said.
"The new information is based on continuing analysis of radar data between the South China Sea and the Strait of Malacca before radar contact was lost (with the missing plane)," AMSA said.
"It indicated that the aircraft was travelling faster than previously estimated, resulting in increased fuel usage and reducing the possible distance the aircraft travelled south into the Indian Ocean."
The new area is closer to land, meaning planes can spend more time searching before having to return to refuel, and the weather is expected to be better there.
The new search area "has moved out of the Roaring Forties (strong westerly winds), which creates very adverse weather frequently", AMSA chief John Young told reporters in Canberra.
Satellite sightings of unidentified debris in recent days have raised hopes of finding wreckage from the Boeing 777, which vanished on March 8 with 239 people on board after veering sharply off course during a flight from Kuala Lumpur to Beijing and flying thousands of miles southwards.
Malaysia believes the plane was deliberately redirected by someone on board, but nothing else is known.
Thailand Thursday reported a sighting of 300 floating objects. Japan also announced a satellite analysis indicated around 10 square floating objects, although it was not clear if these were in the zones the new search would focus on.
Japan's Cabinet Satellite Intelligence Centre's study showed the objects it sighted on Wednesday were up to eight metres in length and four metres wide. Jiji Press cited an official at the office as saying they were "highly likely" to be from the plane.
The Thai and Japanese sightings came after satellite data from Australia, China and France had also shown floating objects possibly related to flight MH370. But nothing has so far been retrieved despite the huge multinational search.
"This is a credible new lead and will be thoroughly investigated today," Australian Prime Minister Tony Abbott said of the revised search area.
The updated advice was provided by an international investigation team in Malaysia, with the Australian Transport Safety Bureau determining "that this is the most credible lead to where debris may be located".
The new search area measures about 319,000 square kilometres (127,600 sq miles) and is around 1,850 kilometres west of Perth. Australia is re-positioning its satellites to focus on it.
Black box deadline
As the search intensifies, the United States said it was sending a second P-8 Poseidon -- an advanced surveillance plane -- to Perth.
Thursday's suspension of the air search caused mounting concern as the clock ticks on the tracking signal emitted by the plane's "black box" of flight data.
It will expire after roughly 30 days, around April 8.
The US Pacific Fleet has moved a Towed Pinger Locator hydrophone and Bluefin-21 Side-scan sonar to Perth, to try to locate the box as soon as an approximate crash site is established.
"It's critical to continue searching for debris so we can reverse-forecast the wind, current and sea state since March 8th to recreate the position where MH370 possibly went into the water. We've got to get this initial position right prior to deploying the Towed Pinger Locator since the MH370's black box has a limited battery life and we can't afford to lose time searching in the wrong area," said Commander Tom Moneymaker, US 7th Fleet oceanographer.
Seeking closure, anguished families of those aboard are desperately awaiting solid evidence that might unlock one of aviation's greatest riddles.
Until then, several of them refuse to accept the Malaysian government's announcement -- based on a complex British analysis of satellite data -- that the plane was lost at sea.
Two-thirds of the passengers were from China and relatives there have accused the Malaysian government and airline of a cover-up and of botching their response.
In a letter to Beijing's special envoy in Kuala Lumpur, they denounced Malaysia's handling of the search and asked the Chinese government to set up its own "investigation office".
A committee set up by relatives has also been in contact with US lawyers about a possible lawsuit against Malaysia Airlines.
"We question Malaysia's motivations in misleading and delaying so as to miss the best moment to find MH370," the relatives wrote in the letter to special envoy Zhang Yesui Thursday, blasting Kuala Lumpur's behaviour as "irresponsible" and "inhumane".
"We earnestly request that China establish an investigation office into MH370."