Malaysian Prime Minister Najib Razak said Monday that new information from satellite data showed missing Malaysia Airlines Flight MH370 "ended in the southern Indian Ocean.” (AP)

Malaysian Prime Minister Najib Razak confirmed Monday that the plane that has been missing for 16 days went down in a remote corner of the Indian Ocean, ending hope for survivors among the 239 people on board.

The conclusion was based on satellite data rather than the discovery of any wreckage in the massive search area, located more than 1,500 miles west of Australia.

Najib said new information on the fate of the aircraft came from Britain’s Air Accidents Investigation Branch and the British Inmarsat satellite communications company, which previously had provided data indicating that Malaysian Airlines Flight 370 took either a northern or southern route after diverting from its flight path.

The Malaysian leader said that after making further calculations and “using a type of analysis never before used in an investigation of this sort,” Inmarsat had essentially eliminated the northern route and “concluded that Flight 370 flew along the southern corridor.”

“It is, therefore, with deep sadness and regret that I must inform you that, according to this new data, Flight MH370 ended in the southern Indian Ocean,” Najib said.

What happened to Flight 370?

His announcement touched off grief and anger among passengers’ families gathered in Kuala Lumpur and in Beijing, where the plane was headed March 8.

China, which had 150 passengers on the flight, demanded that Malaysia “provide all data and information that points to this conclusion.”

“China’s search will continue,” said Hong Lei, a spokesman for the Foreign Ministry. “We hope the Malaysian side and other countries will continue to search.”

On Tuesday morning, the ­Australian-led search team said it was suspending its operations for the day because of rough weather. The sole ship in the search left the area in the morning and was headed south for the time being. The weather in this part of the southern Indian Ocean can be extreme. Winds on Tuesday are expected to be as high as 50 mph and will be accompanied by heavy rain. There also will be a low cloud cover with a ceiling of 200 to 500 feet.

Meteorologists expect the weather to improve in the evening and over the next few days, according to the Australian Maritime Safety Authority (AMSA). The agency said search operations should pick up Wednesday, so long as the weather cooperates.

So far, reports of floating objects have proved inconclusive.

“Unfortunately, there’s a lot of debris in the ocean all the time, and it ranges from really teeny-tiny pieces of plastic, up to fishing gear. It can be boats, it can be shipping containers,” said Nancy Wallace, director of the marine debris program at the National Oceanic and Atmospheric Administration.

In a text message to relatives of the passengers, the airline said: “Malaysia Airlines deeply regrets that we have to assume beyond any reasonable doubt that MH370 has been lost and that none of those on board have survived.”

At a press conference Tuesday, Malaysia Airlines chief executive Ahmad Jauhari Yahya said the airline had done everything possible to reach nearly 1,000 family members in person or over the phone, and only used the text messages to make sure everyone learned of the news before it was reported by the media.

He declined to comment on the investigation into what may have happened to the passenger jet.

“We do not know why,” said Ahmad Jauhari. “We do not know how.”

In Beijing, family members of passengers were called to the second floor of the Lido hotel to receive the news. Some relatives fainted or were overcome with grief and simply lay on the ground. Others sat quietly in the corners, red-eyed and sniffling.

One woman cried loudly and said her only son, his wife and their 2-year-old daughter were on the plane.

“Come home, my son! Please. Your mother is still waiting for you!” she wailed inconsolably.

Elsewhere in the room, some responded in anger, throwing chairs and getting into scuffles. Some were angry that they received the news from a Malaysian briefing. Some were angry that they received the news via text message. Some accused the Chinese government of being too weak and not being more forceful with Malaysian officials.

Many had grown to thoroughly distrust the Malaysian authorities.

“They are using a bigger lie to cover their previous lies,” one man insisted.

Data from enigmatic signals

The announcement Monday came after a weekend breakthrough in the analysis of the plane’s most likely flight path.

For six hours after all communication from the airplane ceased March 8, it continued to engage in a computer “handshake” with a satellite that orbits the Earth 22,000 miles above the surface. The satellite always remains above the same point on the equator in the Indian Ocean. Inmarsat, the satellite company, examined the “pings” transmitted from the airplane every hour and, according to the company’s senior vice president, Christopher McLaughlin, detected a Doppler shift in the radio waves. (A Doppler shift is what causes the perceived change in the sound of, say, a passing train or ambulance.)

The analysts concluded that the airplane was moving away from the satellite. That, by itself, did not reveal whether the plane was flying north to Asia or south to the Indian Ocean. But, with help from an unnamed European aerospace expert and from Boeing, Inmarsat scrutinized the pings from other Malaysia Airlines Boeing 777s flying to the north and to the south.

“In looking at the two plots, the correlation between the pings that we found and the southern route plot is absolutely the most compelling. The northern route has no correlation,” McLaughlin said.

“No one at Inmarsat has ever tried to do this or ever had a need to do this, but they intelligently scratched their head and interpreted this tiny bit of data and they were able to measure this signal,” said Scott Madry, an expert on satellite telemetry and a faculty member at the International Space University in Strasbourg, France.

And there was more information squeezed from those enigmatic signals: The pings indicated that the plane was flying at a constant altitude and speed, which McLaughlin said “sort of points to it being on autopilot.”

The plane typically flies on autopilot at 450 nautical mph, he said. That gave authorities a rough idea of how far the jet is likely to have flown. There were six hourly pings after the plane disappeared, but not a seventh because the aircraft presumably ran out of fuel.

McLaughlin noted that there were operational phones in the jet’s business class. None was used.

“They were either turned off or the passengers were incapacitated,” he said.

Reports of floating objects

The statements from Najib and the airline came after observers on a Chinese search plane on Monday spotted some “suspicious objects” in the southern Indian Ocean — two large objects and many smaller white ones.

With the search now in its third week, crew members on an Australian plane separately were able to see two objects, one gray or green and circular and the other an orange rectangle, in another section of the 42,500-square-mile stretch of the southern Indian Ocean where observers have tried for days to find some sign of the missing airliner.

Until those observations, the sighting of possible plane debris has largely been confined to satellite images, making Monday’s visual sighting by human spotters aboard planes a potentially significant breakthrough in the massive search, one of the largest in aviation history.

The mission has been daunting. On Monday, just as soon as objects were spotted by the Chinese, they disappeared again. A U.S. Navy plane sent to investigate the spot 1,353 miles southwest of Perth, Australia, was unable to relocate the debris.

It was unclear whether any of the objects spotted by observers were the same as those recorded in various satellite images, including a grainy one from the Chinese over the weekend showing a “suspicious floating object” 74 feet long and 43 feet wide.

A race against time

Finding the debris field is critical to locating the aircraft’s cockpit recorders.

An underwater emergency beacon on a black box is designed to send a signal with a reach of two nautical miles. Its pings generally have a range of one to three miles, depending on ocean conditions and the terrain of the ocean floor.

“The more noise there is, the harder it is for the signal to be picked up,” said a U.S. official familiar with the operation. “There are a variety of noises in the ocean, and the range of the pinger also is affected by thermal layers.”

The beacon, activated when it comes in contact with water, has a battery life of 30 days.

“It might go longer,” said the official, who was not authorized to speak publicly about the investigation. “But it’s not going to go two or three months. It might go 35 days.”

With 16 days gone since the plane disappeared, the pings are expected to end within two weeks.

“The signal doesn’t gradually get weaker. It just goes dead,” the official said.

If the beacon pings are to be useful, the search must home in on a compact area before the signals stop.

“The classical way to search deep water is to lower behind a boat and tow a sonar system,” said Dave Gallo, of the Woods Hole Oceanographic Institution, who directed the search for the black box on Air France Flight 447, which went down in the Atlantic in 2009. “It’s a sled carrying sonars, normally in about 4,000 meters of water, so you’d have miles of cable behind the boat. You can tow probably at two miles an hour or less because of the strain on the cable.”

The search is being conducted over a vast amount of very deep ocean with a mountainous floor. Swirling currents and winds may have carried any debris hundreds of miles from the spot where the rest of the plane lies on the ocean floor.

Mike Barton, the rescue coordination chief at the AMSA, said the biggest challenge is the search area’s “remoteness from anywhere.” That means search planes are operating at the limits of their fuel supply, he said.

If planes can find any of the floating objects or any new ones of interest, the next step will be to get a ship to the area and fish them out of the water.

“Until we find them and have a good look at them, it’s hard to say if they have anything to do with the aircraft,” Barton said at a news conference in Canberra, the Australian capital.

Wan reported from Beijing, and Halsey reported from Washington. Joel Achenbach, Scott Higham and William Branigin in Washington and Simon Denyer in Kuala Lumpur contributed to this report.