A new analysis of satellite data indicates the missing Malaysia Airlines plane crashed into a remote corner of the Indian Ocean, Malaysian Prime Minister Najib Razak said Monday.
The news is a major breakthrough in the unprecedented two-week struggle to find out what happened to Flight 370, which disappeared shortly after takeoff from Kuala Lumpur to Beijing with 239 passengers and crew aboard on March 8.
But with the location of the plane 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, Najib announced the news in a brief statement to reporters late Monday night, saying the information was based on an unprecedented analysis of satellite data from Inmarsat.
He said the data indicated the plane 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."
He said Malaysia Airlines has informed the families of passengers of the plane's fate.
"For them the past few weeks have been heartbreaking," Razak said. "I know this news must be harder still."
3/24/2014 Related Story: MH 370 Search: Chinese, Australian Planes Spot 'Objects' In Indian Ocean
Relatives of passengers in Beijing had been called to a hotel near the airport to hear the news, and some 50 of them gathered there. 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 in Kuala Lumpur.
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 poured 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."
Before the prime minister's announcement, CBS News correspondent Seth Doane spoke to the wife of a crew member, who is still trying to "pretend" that her husband is around.
Jacqui Gonzales told Doane that she still texts her husband, including one message that said: "Come home, we're waiting."
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 the Inmarsat satellite 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.
Malaysia's police chief, Inspector General Khalid Abu Bakar, reiterated at a news conference Monday that all the passengers had been cleared of suspicion.
But he said the pilots and crew were still being investigated. He would not comment on whether investigators had recovered the files that were deleted a month earlier from the home flight simulator of the chief pilot.
Malaysia Airlines chief executive Ahmad Jauhari Yahya said co-pilot Fariq Abdul Hamid had just transitioned to flying Boeing 777s from other commercial planes and the missing flight was his sixth on that type of aircraft.
Fariq had passed all training requirements to fly without incident, Ahmad said.
Several U.S. lawmakers on Sunday panned the Malaysian government's role in the search for the jetliner, accusing the Malaysians of withholding information and bungling the crucial early days of the search.
Rep. Michael McCaul, R-Texas, who chairs the House Homeland Security Committee, said the Malaysian government squandered the early days of the search looking for the plane in Central Asia when it was likely to be found in the southern Indian Ocean.
CBS News Aviation and Safety Expert Captain Chesley "Sully" Sullenberger said on "Face the Nation" that some "missteps" early in the investigation have impaired the search effort.
"Here we are...into the third week of the investigation and just now beginning to re-narrow the search to areas that are still as large as the United States," he said.