Datuk Hishammuddin Hussein (L), acting Minister of Transport and Malaysian Prime Minister Najib Abdul Razak update the media on the search and rescue plan for the missing MAS Airlines flight MH370 during a press conference on March 15, 2014 in Kuala Lumpur, Malaysia.How Foo Yeen/Getty Images
A Malaysian passenger jet missing for more than a week had its communications deliberately disabled and its last signal came about seven-and-a-half hours after takeoff, meaning it could have ended up as far as Kazakhstan or deep in the southern Indian Ocean, Prime Minister Najib Razak said Saturday
Najib's statement Saturday gave further credence to mounting speculation that the disappearance of the Malaysia Airlines Boeing 777 with 239 people on board was not accidental.
It also underlines the massive task for searchers who, having already scoured vast areas of ocean, will now call off the massive search operation focused strictly on South China Sea. The current search there involved 14 countries, 43 ships and 58 aircraft.
"In view of this latest development, the Malaysian authorities have refocused their investigation into the crew and passengers on board," Najib said, stressing they are still investigating all possibilities as to why the plane deviated so drastically from its original flight path.
"Clearly the search for MH370 has entered a new phase," Najib told a televised news conference.
Minutes after the Malaysian press conference ended, police began searching the house of the missing aircraft's 53-year-old captain for any evidence that he could have been involved in foul play, Reuters reported.
But to date, no details have emerged of any passengers or crew members having any links to terrorist groups, nor any evidence of psychological problems that may explain a motive for diverting or deliberately crashing the flight. And Malaysia Airlines officials have said they do not believe that the experienced pilot would have sabotaged the plane.
Despite the major new twist in the investigation, however, the prime minister still urged caution in jumping to conclusions.
"Despite media reports the plane was hijacked, I wish to be very clear, we are still investigating all possibilities as to what caused MH370 to deviate," Najib said.
Click here for more Al Jazeera America coverage on Flight MH370
After Malaysian Airlines flight 370 left from Kuala Lumpur heading to Beijing at 12:40 a.m. on March 8, the plane subsequently lost communications with civilian air controllers at about 1:20 a.m. and the plane went missing in one of the most puzzling mysteries in modern aviation history.
Najib said investigators now have a high degree of certainly that one of the plane's communications systems, the Aircraft and Communications Addressing and Reporting System, was disabled before the aircraft reached the east coast of Malaysia. Shortly afterward someone on board then switched off the aircraft's transponder, which communicates with civilian air traffic controllers.
After that point, the prime minister confirmed, Malaysian air force defense radar showed evidence of the plane turning back westward, crossing over peninsular Malaysia into the northern stretches of the Strait of Malacca. Authorities previously had said this radar data could not be verified.
The Malaysian P.M. said the last confirmed signal between the plane and a satellite came at 8:11 a.m. Malaysian time — 7 hours and 31 minutes after take-off. Airline officials have said the plane had enough fuel to fly for up to about eight hours.
"The investigations team is making further calculations which will indicate how far the aircraft may have flown after this last point of contact," he said.
Najib said authorities had determined that the plane's last communication with a satellite was in one of two possible "corridors" — a northern one from northern Thailand through to the border of Kazakstan and Turkmenistan, and a southern one from Indonesia to the southern Indian Ocean.
Those corridors represent a satellite track, which appears as an arc on a map. The plane did not necessarily follow the corridor, but was at some point along its path at the moment the signal was sent.
Al Jazeera and wire services