KUALA LUMPUR, Malaysia (CNN) -- Stormy weather grounded search planes scheduled to hunt for the Malaysia Airlines plane in the Indian Ocean on Tuesday, authorities said.
Gale-force winds, large waves, heavy rain and low clouds forecast for the area "would make any air and sea search activities hazardous and pose a risk to crew," the Australian Maritime Safety Authority said. Boats and aircraft will resume searching Wednesday if weather permits, officials said.
The unexpected delay in a search that has grabbed global attention came just hours after Malaysia's Prime Minister confirmed the worst fears of the families of those aboard Flight 370, announcing that the missing plane went down somewhere in the southern Indian Ocean.
New analysis of satellite data by a British satellite company and accident investigators led to that conclusion, Prime Minister Najib Razak said Monday.
"They have told us all lives are lost," a missing passenger's relative briefed by the airline in Beijing said.
While the last-minute announcement appeared to end hopes of finding survivors more than two weeks after the flight vanished, it left many key questions unanswered, including what went wrong aboard the Beijing-bound airliner and the location of its wreckage in the deep, wild waters of the Indian Ocean.
Families overcome after hearing the news
For families, some of whom had held out hope their relatives somehow were still alive, the news appeared to be devastating. At a briefing for relatives in Beijing, some were overcome and had to be taken from a hotel on stretchers. In Kuala Lumpur, a woman walked out of a briefing for families in tears.
"My son, my daughter-in-law and granddaughter were all on board. All three family members are gone. I am desperate!" a woman said outside the Beijing briefing.
Another woman came out of the briefing room screaming, expressing doubts about the Malaysian conclusion.
"Where is the proof?" she said. "You haven't confirmed the suspected objects to tell us no one survived."
Sarah Bajc, the partner of one of three Americans aboard the flight, Philip Wood, canceled all media interviews after the announcement.
"I need closure to be certain, but cannot keep on with public efforts against all odds," she wrote. "I still feel his presence, so perhaps it was his soul all along."
A committee representing some of the families of the 154 Chinese and Taiwanese passengers aboard the missing aircraft sharply criticized the Malaysian government in a statement, accusing authorities of deliberate search delays and cover-ups, China's state-run CCTV reported.
"If our 154 relatives aboard lost their lives due to such reasons, then Malaysia Airlines, the Malaysian government and the Malaysian military are the real murderers that killed them," the statement said, according to CCTV.
Malaysian police have interviewed more than 50 people in their investigation into the missing plane, Inspector-General of Police Tan Sri Khalid Abu Bakal told Malaysia's national news agency Bernama.
He said police are focusing on four possibilities about what happened: a potential hijacking, sabotage, psychological issues or personal problems of the passengers and/or crew.
"Such cases may take up to a year," Khalid said, "so please don't jump to conclusions that the police are slow."
While investigators have yet to find even a piece of the plane, the Prime Minister based his announcement on what he described as unprecedented analysis of satellite data by British satellite provider Inmarsat and the British Air Accidents Investigation Branch. He didn't describe the nature of the analysis.
He said the data, drawn from satellite pings the ill-fated airliner continued to send throughout its final flight, made it clear that the plane's last position was in the middle of the southern Indian Ocean, "far from any possible landing sites."
He begged reporters to respect the privacy of relatives.
"For them, the past few weeks have been heartbreaking," he said. "I know this news must be harder still."
The Prime Minister's statement came after the airline sent a text message to relatives saying it "deeply regrets that we have to assume beyond any reasonable doubt that MH370 has been lost and that none of those onboard survived."
The airline said it was making plans to fly families to Australia once wreckage is found.
Two objects in the Indian Ocean
The announcement came the same day as Australian officials said they had spotted two objects in the southern Indian Ocean that could be related to the flight, which has been missing since March 8 with 239 people aboard.
One object is "a gray or green circular object," and the other is "an orange rectangular object," the Australian Maritime Safety Authority said.
Hishammuddin Hussein, Malaysia's acting transportation minister, said Monday that Australian authorities hoped to retrieve the objects by Tuesday morning. The Australian naval ship HMAS Success was steaming toward the location at last word Monday evening.
The objects are the latest in a series of sightings, including "suspicious objects" reported earlier Monday by a Chinese military plane that was searching in the same area, authorities said.
A U.S. surveillance plane sent to follow up was unable to find the objects, and so far, none of the sightings has been definitively linked to Flight 370.
Ten aircraft -- from Australia, China, the United States and Japan -- searched the area Monday.
China said Monday after the Prime Minister's announcement that it would be sending more ships to help.
China has a particularly large stake: Its citizens made up about two-thirds of the passengers on the missing Boeing 777.
Satellites helped focused the search
Amid a vast regional search that at one point spanned nearly 3 million square miles, searchers homed in on the southern Indian Ocean in recent days after satellite images spotted a variety of unknown objects in an area roughly 1,500 miles southwest of Perth, Australia.
Australia reported the first images in the area, followed by China and France.
The area also lies on a projected flight path for the aircraft calculated in part from the satellite pings sent by the plane after other communications systems had shut down.
Australian officials have repeatedly warned that the objects may not be from the missing plane. They could be containers that have fallen off cargo ships, for example.
On Saturday, searchers found a wooden pallet as well as strapping belts, Australian authorities said. Hishammuddin said Monday that wooden pallets were among the items on Flight 370. But such pallets are also common in the ocean shipping industry, so it they may be unrelated to the flight.
The investigation into the passenger jet's disappearance has already produced a wealth of false leads and speculative theories. Previously, when the hunt was focused on the South China Sea near where the plane dropped off civilian radar, a number of sightings of debris proved to be unrelated to the search.
Plane said to have flown low
Monday's dramatic developments came after a weekend during which other nuggets of information emerged about the movements of the errant jetliner on the night it vanished.
Military radar tracking shows that after making a sharp turn over the South China Sea, the plane changed altitude as it headed toward the Strait of Malacca, an official close to the investigation into the missing flight told CNN.
The plane flew as low as 12,000 feet at some point before it disappeared from radar, according to the official. It had reportedly been flying at a cruising altitude of 35,000 feet when contact was lost with air traffic control.
The sharp turn seemed to be intentional, the official said, because executing it would have taken the Boeing 777 two minutes -- a period during which the pilot or co-pilot could have sent an emergency signal if there had been a fire or other emergency.
Authorities say the plane didn't send any emergency signals, though some analysts say it's still unclear whether the pilots tried but weren't able to communicate because of a catastrophic failure of the aircraft's systems.
The official, who is not authorized to speak to the media, told CNN that the area the plane flew in after the turn is a heavily trafficked air corridor and that flying at 12,000 feet would have kept the jet well out of the way of that traffic.
Was plane's route reprogrammed?
Also over the weekend, Malaysian authorities said the last transmission from the missing aircraft's reporting system showed it heading to Beijing -- a revelation that appears to undercut the theory that someone reprogrammed the plane's flight path before the co-pilot signed off with air traffic controllers for the last time.
That reduces, but doesn't rule out, suspicions about foul play in the cockpit.
Last week, CNN and other news organizations, citing unnamed sources, reported that authorities believed someone had reprogrammed the aircraft's flight computer before the sign-off.
CNN cited sources who believed the plane's flight computer must have been reprogrammed because it flew directly over navigational way points. A plane controlled by a human probably would not have been so precise, the sources said.
Malaysian authorities never confirmed that account, saying last week that the plane's "documented flight path" had not been altered.
On Sunday, they clarified that statement further, saying the plane's automated data reporting system included no route changes in its last burst, sent at 1:07 a.m. -- 12 minutes before the last voice communication with flight controllers.
Analysts are divided about what the latest information could mean. Some argue it's a sign that mechanical failure sent the plane suddenly off course. Others say there are still too many unknowns to eliminate any possibilities.
CNN aviation analyst Miles O'Brien called the fresh details about the flight a "game changer."
"Now we have no evidence the crew did anything wrong," he said. "And in fact, now, we should be operating with the primary assumption being that something bad happened to that plane shortly after they said good night."
If a crisis onboard caused the plane to lose pressure, he said, pilots could have chosen to deliberately fly lower to save passengers.
"You want to get down to 10,000 feet, because that is when you don't have to worry about pressurization. You have enough air in the atmosphere naturally to keep everybody alive," he said. "So part of the procedure for a rapid decompression ... it's called a high dive, and you go as quickly as you can down that to that altitude."
Authorities have said pilot Zaharie Ahmad Shah was highly experienced. On Monday, Malaysian authorities said Flight 370 was co-pilot Fariq Abdul Hamid's sixth flight in a Boeing 777, and the first time when he was not traveling with an instructor pilot shadowing him.
"We do not see any problem with him," said Malaysia Airlines CEO Ahmad Jauhari Yahya.
Michael Pearson wrote and reported from Atlanta; Mitra Mobasherat reported from Kuala Lumpur; CNN's Pauline Chiou, David McKenzie and Yuli Yang contributed from Beijing; CNN's Jim Sciutto, Will Ripley, Sara Sidner, Catherine E. Shoichet, Kevin Wang, Ram Ramgopal, Evan Perez, Kyung Lah and Jaime A. FlorCruz contributed to this report.