Rain was expected to hamper the hunt for the missing Malaysia Airlines jet on Monday as search teams headed out at first light into an expanded are of the Indian Ocean.
The Australian Maritime Safety Authority's rescue coordination centre said the search area had been expanded from 59,000 to 68,500 square kilometres, including a new separate area following radar information provided by France yesterday.
Nasa said its scientific satellites were also being used to scour the ocean for objects and that it was trawling through archive data in an effort to spot any clues as to the plane's whereabouts.
Australian Transport Minister Warren Truss said early on Monday that “nothing of note” was found Sunday, which he described as a “fruitless day".
“It’s going to be a challenge, but we’ll stick at it,” he told Australian Broadcasting Corporation radio before the first aircraft left Perth at dawn.
“We’re just, I guess, clutching at whatever little piece of information comes along to try and find a place where we might be able to concentrate the efforts,” he added.
Malaysia yesterday received a batch of 'radar echoes' - electronic signals sent out that can bounce back information about the location of objects - this time from French authorities, showing possible debris from the missing Malaysia Airlines plane in the southern Indian Ocean.
An unnamed Malaysian official said yesterday the data was compiled on Friday. The location was about 930 kilometres north of where objects in images released by China and Australia were located.
"Malaysia immediately relayed [this] to the Australian rescue co-ordination centre," Malaysia's transport ministry said.
Two Chinese Ilyushin IL-76 aircraft will today start searching for potential wreckage in an isolated stretch of the Indian Ocean. It is hoped that any objects recovered may lead to clues on the whereabouts of the plane and the 239 people it was carrying, 154 of whom were Chinese.
A growing international fleet of aircraft and vessels in an Australia-led Indian Ocean search mission found nothing on the fourth day of scouring an area 2,300 kilometres west of Perth.
The Australian Maritime Safety Authority said in a statement Monday that it “reiterates this is a challenging search operation”.
“The flight has been missing since March 8 and AMSA continues to hold the gravest of concerns for the passengers and crew on board the missing flight.”
Today’s search is split into two areas within the same proximity covering a cumulative 68,500 square kilometres,” it said.
“The weather forecast in the search area is expected to deteriorate, with rain likely," it added.
Ships and aircraft scrambled to search for a wooden pallet and other debris after a civilian search plane spotted the objects on Saturday, 14 days after Beijing-bound Flight MH370 vanished after taking off from Kuala Lumpur.
Mike Barton, who is a rescue co-ordinator for the Australian Maritime Safety Authority (AMSA), said the search team saw "a wooden pallet and a number of other items … [including] strapping belts of different lengths".
Watch: Pallet, belts sighted in Australia hunt for MH370
An official with Malaysia Airlines confirmed last night that the plane was carrying wooden pallets but provided no further details. The official spoke on condition of anonymity because of company policy preventing the official from being named.
Nasa said it would use high-resolution cameras aboard satellites and the International Space Station to look for possible crash sites in the Indian Ocean.
The US space agency is also mining archived images collected by instruments on its Terra and Aqua environmental satellites, said Nasa spokesman Allard Beutel.
"Our satellites and space-based cameras are designed for long-term scientific data gathering and Earth observation. They’re really not meant to look for a missing aircraft, and obviously Nasa isn’t a lead agency in this effort. But we’re trying to support the search, if possible," Beutel said.
Watch: Australia continues search for Malayasian Airlines MH370
After more than two weeks of not knowing the fate of the vanished aircraft or any of its passengers, the world awaits any news on the objects of interest identified by French, Australian and Chinese satellites. Search and rescue teams have been struggling to narrow search areas.
The plane's black box - which will be critical in determining what actually happened on board the flight - has only about 13 days of battery left.
Barton said AMSA had been able to search a smaller "defined area" based on two previous satellite images showing possible objects in the immediate vicinity.
Australian Prime Minister Tony Abbott said yesterday: "Obviously, we have now had a number of very credible leads and there is increasing hope, no more than hope, that we might be on the road to discovering what did happen."
Additional reporting by Associated Press