Australian Prime Minister Tony Abbott on Monday admitted it was "highly unlikely" that any surface wreckage from missing Flight MH370 will be found as he announced a more intensive underwater search.
"I am now required to say to you that it is highly unlikely at this stage that we will find any aircraft debris on the ocean surface," he said. The Malaysian Airlines plane disappeared on March 8, and extensive search efforts and multiple false leads haven’t brought searchers any closer to finding it.
Abbott told reporters in Canberra that the U.S. Navy's Bluefin 21 has finished scouring the initial search area far off the Australian west coast and did not find anything.
"It is now 52 days since Malaysia Airlines Fight MH370 disappeared, and I'm here to inform you that the search will be entering a new phase," Abbott said at a news conference.
Radar and satellite data show the jet, carrying 239 passengers and crew members, veered far off course on March 8 for unknown reasons during a flight from Kuala Lumpur to Beijing. Analysis indicates it would have run out of fuel in the remote section of ocean where the search has been focused. No parts of the plane have been recovered since the massive multinational hunt began.
The Bluefin's original search area was a circle with a six-mile radius, in water almost three miles deep, around a spot where signals consistent with airplane black box pings were heard on April 8.
"I want the families to know — I want the world to know— that Australia will not shirk its responsibilities in this area. We will do everything we humanly can ... to solve this mystery," Abbott said. "We will not let people down, and while the search will be moving to a new phase in coming weeks, it certainly is not ending."
Malaysia, China, Japan, New Zealand, South Korea, Britain and the United States are assisting Australia in carrying out the most expensive search in aviation history.
At a news conference on Sunday in Kuala Lumpur with Malaysian Prime Minister Najib Razak, President Barack Obama said, "I can tell you the United States is absolutely committed to providing whatever resources and assets that we can."
"Obviously we don't know all the details, but we do know if in fact the plane went down in the ocean on this part of this world, there is a big place, and it is very challenging," he said. "It is going to take quite some time."
A U.S. defense official told Reuters on Friday that the sea search is likely to drag on for years as it enters the much more difficult phase of scouring broad areas of the ocean where the plane is believed to have crashed.
Malaysia and Australia are under pressure to bring closure to the grieving families of those on board MH370 by finding wreckage to determine what happened to the aircraft.
Malaysia is also under growing pressure to improve its disclosure about its investigation, although Obama said on Sunday that U.S. authorities found Kuala Lumpur "fully forthcoming" in sharing information. Razak has said his government would make public a preliminary report on the plane's disappearance next week.
Last week Malaysian Transport Minister Hishammuddin Hussein told reporters that authorities would be "increasing the assets that are available for deep-sea search" and that the government was seeking help from state oil company Petronas, which has expertise in deep-sea exploration.
The empty expanse of water — some 1,000 miles northwest of Western Australia's capital, Perth — is one of the most remote places in the world and one of the deepest.
Al Jazeera and wire services