PERTH, Australia - Spotter planes on Friday scoured a remote, storm-tossed stretch of the Indian Ocean for wreckage from a Malaysian jet, as Chinese relatives of the missing passengers clashed with Malaysian officials over their handling of the search operation.
The Australian and US aircraft flew back and forth over an isolated section of ocean 2,500 kilometres (1,500 miles) southwest of Perth, looking for two floating objects that had shown up on grainy satellite photos taken several days before.
Although the images were too indistinct to confirm as debris from Flight MH370, Australian and Malaysian officials said they represented the most "credible" leads to date in the hunt for the plane and its 239 passengers and crew.
The Australian Maritime Safety Authority (AMSA) said the planes flew low under the cloud cover Friday rather than rely on radar, after poor weather the day before hampered the search.
"We replanned the search to be visual, so aircraft flying relatively low, with very highly skilled observers looking out of the windows," said AMSA official John Young.
"This means aircraft operating more closely together and we will need more aircraft for this task." Friday's aerial contingent comprised three Australian air force P-3 Orions, a US Navy P-8 Poseidon and a civil Bombardier Global Express jet.
"We have not found anything concrete yet," Malaysian Transport Minister Hishammuddin Hussein told reporters in Kuala Lumpur.
The great distance from the west coast of Australia allows the planes only about two hours of actual search time before they must turn around with enough fuel to get back to Perth.
A Norwegian merchant ship is already helping at the search area, but Australia's HMAS Success, which is capable of retrieving any wreckage, was still days away.
'We owe it to the families'
The satellite images were first announced in parliament by Australian Prime Minister Tony Abbott, who defended himself Friday against suggestions he may have "jumped the gun." "We owe it to the families and the friends and the loved ones ... to give them information as soon as it's to hand," he said.
Abbott said he had spoken to Chinese President Xi Jinping who he described as "devastated" by the disappearance of MH370 and the 153 Chinese nationals on board.
"This has been a gut-wrenching business for so many people," the prime minister said.
Malaysia has been criticised for its handling of the crisis, especially by Chinese relatives who have accused authorities and the flag-carrier airline of providing insufficient or misleading information.
A delegation of Malaysian government and military officials flew to Beijing for what turned out to be a bad-tempered meeting with relatives.
The event began with family members yelling at delegates to stand up when they were being introduced.
"You have wasted so much time," shouted one anguished relative.
The nature of the events that diverted MH370 from its intended flight path on March 8 remain shrouded in mystery, although Malaysian investigators have stuck to their assumption that it was the result of a "deliberate action" by someone on board.
Three scenarios have gained particular attention: hijacking, pilot sabotage, and a sudden mid-air crisis that incapacitated the flight crew and left the plane to fly on auto-pilot for several hours until it ran out of fuel and crashed.
If the objects in the remote southern Indian Ocean are shown to have come from MH370, some analysts believe the hijacking theory will lose ground.
"The reasonable motives for forcing the plane to fly there are very, very few," Gerry Soejatman, a Jakarta-based independent aviation analyst, told AFP.
The area is far from recognised shipping lanes, and the Norwegian car transporter was understood to have taken two days to reach it.
"It's really off the beaten track," said Tim Huxley, chief executive of Wah Kwong Maritime Transport Holdings in Hong Kong. "It's a lonely, lonely place." Sarah Bajc, the partner of American passenger Philip Wood, said she had clung to the notion of a hijacking plot that might result in the passengers' eventual safe return.
"So if this debris is indeed part of that plane, then it kind of dashes that wishful thinking to pieces," Bajc told CNN.
"So I really hope it's not a part of the plane, but, you know, if it is, then at least we can go down another path of deciding that maybe we need to start preparing for another scenario instead." The satellite images were taken on March 16, meaning the objects would have been drifting for days in a volatile maritime region.
If debris is found, the mammoth task remains of locating the "black box" flight data recorder, which offers the best chance of peeling back the layers of confusion and mystery surrounding MH370.
There has been little progress in what essentially became a criminal investigation after it was determined that the disappearance of the plane was probably deliberate.
Malaysia has asked the FBI to help recover data it said was deleted from a home flight simulator belonging to the plane's chief pilot, Captain Zaharie Ahmad Shah, but otherwise no evidence has emerged to implicate him.