But with the location of Flight 370 itself still unknown – most likely somewhere at the bottom of the sea – profound questions remain about what brought down the aircraft and why.
Dressed in a black suit, Prime Minister Najib Razak announced the news in a brief statement to reporters late Monday night, saying the information was based on an unprecedented analysis of satellite data.
He said the data indicated that the Boeing 777, which took off from Kuala Lumpur for Beijing on March 8 with 239 passengers and crew, flew "to a remote location, far from any possible landing sites."
"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."
In Beijing, relatives shrieked and sobbed uncontrollably and men and women held up their loved ones when they heard the news. Their grief came pouring out after days of waiting for definitive word on the fate of their relatives aboard the missing plane.
The family members in Beijing had been called to a hotel near the airport to hear the announcement. Afterward, they filed out of a conference room in heart-wrenching grief.
One woman collapsed and fell on her knees, crying "My son! My son!"
In Kuala Lumpur, Selamat Omar, the father of a 29-year-old aviation engineer who was on the flight, said some members of families of other passengers broke down in tears at the news.
"We accept the news of the tragedy. It is fate," Selamat told The Associated Press.
Selamat said the airline hasn’t told the families yet whether they will be taken to Australia, which is coordinating the search for the plane. He said they expect more details Tuesday.
Search teams from 26 nations have pored over radar data and scoured a wide swath of Asia for weeks with advanced aircraft and ships in a deeply frustrating attempt find the plane.
Malaysia Airlines said in a statement to the families that "our prayers go out to all the loved ones of the 226 passengers and of our 13 friends and colleagues at this enormously painful time."
"We know there are no words that we or anyone else can say which can ease your pain," the airline said. "The ongoing multinational search operation will continue, as we seek answers to the questions which remain."
A Malaysia Airlines official, who declined to be named citing company policy, said there are no plans to fly the families to the Australian city of Perth until wreckage is found.
The plane’s disappearance shortly after takeoff from Kuala Lumpur on a routine flight to Beijing has baffled investigators, who have yet to rule out mechanical or electrical failure, hijacking, sabotage, terrorism or issues related to the mental health of the pilots or someone else on board.
Officials have said that the plane automatically sent a brief signal – a "ping" – every hour to a satellite belonging to Inmarsat, a British company, even after other communication systems on the jetliner shut down.
The pings did not include any location information, but an initial analysis showed that the location of the last ping was probably along one of two vast arcs running north and south.
Najib said Inmarsat had done further calculations "using a type of analysis never before used in an investigation of this sort," and had concluded that the plane’s last position was "in the middle of the Indian Ocean, west of Perth."
On Monday, ships rushed to the location of floating objects spotted by Australian and Chinese planes in the southern Indian Ocean close to where multiple satellites have detected possible remains of the lost airliner.
One ship was carrying equipment to detect the plane’s vital black box, but it remained uncertain whether the vessels were approaching a successful end to the search or another frustrating dead end.
Associated Press writers Scott McDonald in Kuala Lumpur and Ian Mader and Christopher Bodeen in Beijing contributed to this report.
(Copyright 2014 The Associated Press. All rights reserved.)