KUALA LUMPUR, Malaysia — China demanded that Malaysia turn over the satellite data used to conclude that a Malaysia Airlines jetliner had crashed in the southern Indian Ocean, killing everyone on board, as gale-force winds and heavy rain on Tuesday halted the search for remains of the plane.
The weather is expected to improve so that the multinational search being conducted out of Perth, Australia, could possibly resume Wednesday. But the searchers will face a daunting task of combing a vast expanse of choppy seas for suspected remnants of the aircraft sighted earlier.
"We're not searching for a needle in a haystack — we're still trying to define where the haystack is," Australia's deputy defense chief, Air Marshal Mark Binskin, told reporters at a military base in Perth as idled planes stood behind him.
Australian and Chinese search planes spotted floating objects in an area 2,500 kilometers (1,550 miles) southwest of Perth on Monday, but none was retrieved. Now, with the harsh weather and a 24-hour delay in the search, those objects and other possible debris from the plane could drift to an even wider area.
In remarks to the Malaysian Parliament, Prime Minister Najib Razak cautioned that the search will take a long time and "we will have to face unexpected and extraordinary challenges."
Late Monday, Najib announced that the Boeing 777 had gone down in the sea with no survivors. But that's all that investigators and the Malaysian government have been able to say with certainty about Flight 370's fate since it disappeared on March 8 shortly after taking off from Kuala Lumpur for Beijing.
Left unanswered are many troubling questions about why it was so far off course. Experts piecing together radar and satellite data believe the plane back-tracked over Malaysia and then traveled in the opposite direction to the Indian Ocean.
Investigators will be looking at various possibilities including mechanical or electrical failure, hijacking, sabotage, terrorism or issues related to the mental health of the pilots or someone else on board.
"We do not know why. We do not know how. We do not know how the terrible tragedy happened," the airline's chief executive, Ahmad Jauhari Yahya, told reporters.
Monday night's announcement unleashed a storm of sorrow and anger among the families of the plane's 239 passengers and crew — two-thirds of them Chinese. Family members of the missing passengers have complained bitterly about a lack of reliable information and some say they are not being told the whole truth.
Nearly 100 relatives and their supporters marched to the Malaysian Embassy in Beijing, where they threw plastic water bottles, tried to rush the gate and chanted, "Liars!"
Many wore white T-shirts that read "Let's pray for MH370" as they held banners and shouted, "Tell the truth! Return our relatives!"
There was a heavy police presence at the embassy. Police briefly scuffled with a group of relatives who tried to approach journalists.
Deputy Foreign Minister Xie Hangsheng told Malaysia's ambassador that China wanted to know exactly what led Najib to announce that the plane had been lost, a statement on the ministry's website said.
Malaysia Airlines Chairman Mohammed Nor Mohammed Yusof told a news conference Tuesday that it may take time for further answers to become clear.
"This has been an unprecedented event requiring an unprecedented response," he said. "The investigation still underway may yet prove to be even longer and more complex than it has been since March 8th."
He added that even though no wreckage has been found, there was no doubt it had crashed.
"This by the evidence given to us, and by rational deduction, we could only arrive at that conclusion: That is, for Malaysia Airlines to declare that it has lost its plane, and by extension, the people in the plane," he said.
The conclusions were based on a thorough analysis of the brief signals the plane sent every hour to a satellite belonging to Inmarsat, a British company, even after other communication systems on the jetliner shut down for unknown reasons.
The latest satellite information does not provide an exact location but just a rough estimate of where the jet crashed into the sea.
Although there have been an increasing number of apparent leads, there has been no confirmed identification of any debris.
The delay in the search will make it harder for investigators to forensically track back where the plane hit the water if they do find some debris, said Erik van Sebille, an oceanographer at the University of New South Wales in Sydney. The swirling and unpredictable nature of currents can spread items that begin in the same place hundreds of kilometers (miles) apart within weeks.
"It's like one giant pinball machine out there," he said.
Also, there is a race against the clock to find any trace of the plane that could lead searchers to the black boxes, whose battery-powered "pinger" could stop sending signals within two more weeks. The batteries are designed to last at least a month and can last longer.
Several countries have begun moving specialized equipment into the area to prepare for a search for the plane and its black boxes, the common name for the cockpit voice and data recorders, needed to help determine what happened to the jetliner.
An Australian navy support vessel, the Ocean Shield, equipped with acoustic detection equipment, was expected to arrive in the search zone in several days. And the U.S. Pacific Command said it was sending a black box locator to the region in case a debris field is located.
The U.S. Navy has also sent an unmanned underwater vehicle to Perth that could be used if debris is located, said Rear Adm. John Kirby, a Pentagon spokesman. The Bluefin-21, expected to arrive in Perth on Wednesday, has side-scanning sonar and what is called a "multi-beam echo sounder" that can be used to take a closer look at objects under water, he added. It can operate at a depth of 4,500 meters (14,700 feet).
Australian Prime Minister Tony Abbott said he had spoken to Najib to offer help with the ongoing search and investigation.
"What up until now has been a search, moves into a recovery and investigation phase," Abbott said. "I have offered Malaysia, as the country legally responsible for this, every assistance and cooperation from Australia."
The search for the wreckage and the plane's recorders could take years because the ocean is up to 7,000 meters (23,000 feet) deep in some parts. It took two years to find the black box from an Air France jet that went down in the Atlantic Ocean on a flight from Rio de Janeiro to Paris in 2009, and searchers knew within days where the crash site was.
"We've got to get lucky," said John Goglia, a former member of the U.S. National Transportation Safety Board. "It's a race to get to the area in time to catch the black box pinger while it's still working."