KUALA LUMPUR, Malaysia — Malaysia's Prime Minister Najib Razak said Saturday that communications on a Malaysia Airlines flight missing since last Saturday were disabled due to "deliberate action by someone on the plane" and that the last known signal from the airliner came more than seven hours after takeoff.
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The revelation came amid an intensifying search involving dozens of planes and ships in an ever-widening area where the plane may have gone down. Military and government experts on Saturday pored over satellite and radar data that may shed light on the fate of the plane but so far there is no trace of debris.
Speaking at a news conference in Kuala Lumpur, Prime Minister Razak said investigators were making calculations to try to determine exactly how far the airliner traveled after its last point of contact.
According to new satellite data analyzed by the FAA, NTSB, AAIB and Malaysian authorities, the plane's communications from the Aircraft and Communications Addressing and Reporting System were cut off just before the aircraft reached the east coast of the peninsula of Malaysia, and the aircraft's transponder was turned off shortly thereafter, near the border of Malaysia and Vietnam, he said.
Flight MH370 departed from Kuala Lumpur for Beijing at 12:40 a.m. on March 8 with 239 people on board. A multi-national search effort involving 14 countries, 43 ships and 58 aircraft has turned up no trace of the Boeing 777, despite an expansive search that has widened with each passing day.
The last confirmed communication from the plane to a satellite was 8:11 a.m. Malaysia time, Razak said.
The prime minister said the search for flight has entered a "new phase," focusing on two possible corridors -- a northern corridor from the border of Kazakstan and Turkmenistan to northern Thailand, and a southern corridor from Indonesia to the southern Indian Ocean.
The prime minister also confirmed reports that circulated earlier this week that the plane veered off its course toward Beijing, turning back westward and crossing over peninsular Malaysia into the northern stretches of the Strait of Malacca.
Razak announced that search operations were ending in the South China Sea and investigators are refocusing their attention on the pilots and passengers on board Flight MH370. He added that Malaysia was "working with the relevant countries to request all information relevant to the search, including radar data."
Razak would not confirm a hijacking.
"Despite media reports that the plane was hijacked, I wish to be very clear: We are still investigating all possibilities as to what caused MH370 to deviate from its original flight path," he said.
Razak also defended Malaysia's handling of the investigation, saying that they have followed up each and every lead.
According to a report by Reuters, authorities searched the home of the pilot shortly after the prime minister's statement.
"For the families and friends of those involved, we hope this new information brings us one step closer to finding the plane," Razak said.
Indian navy ships supported by long-range surveillance planes and helicopters scoured Andaman Sea islands for a third day on Saturday without any success in finding evidence of the missing jet, officials said.
Nearly a dozen ships, patrol vessels, surveillance aircraft and helicopters have been deployed, but "we have got nothing so far," said V.S.R. Murthy, an Indian coast guard official.
The Indian navy's coordinated search has so far covered more than 250,000 square kilometers (100,579 square miles) in the Andaman Sea and the Bay of Bengal "without any sighting or detection," the Defense Ministry said in a statement.
The search has been expanded to the central and eastern sides of the Bay of Bengal, the ministry said.
India intensified the search on Saturday by deploying two recently acquired P8i long-range maritime patrol and one C 130J Hercules aircraft to the region. Short-range maritime reconnaissance Dornier aircraft have also been deployed, the ministry said.
Bangladesh has joined the search effort in the Bay of Bengal with two patrol aircraft and two frigates, said Mahbubul Haque Shakil, an aide of Bangladesh's prime minister, Sheikh Hasina.
Seeing no headway, Malaysian authorities suggested a new search area of 9,000 square kilometers (3,474 square miles) to India along the Chennai coast in the Bay of Bengal, India's Defense Ministry said.
India used heat sensors on flights over hundreds of uninhabited Andaman Sea islands that stretch south of Myanmar, covering an area 720 kilometers (447 miles) long and 52 kilometers (32 miles) wide. Only 37 of 572 are inhabited, with the rest covered in dense forests.
The island chain has four airstrips, but only the main airport in Port Blair can handle a large commercial jet.
Much of the early search has focused east of Malaysia in the South China Sea, where the aircraft last communicated with air-traffic base stations about an hour after departing for Beijing.
Three days ago, six Indian navy and coast guard ships, plus reconnaissance planes, began searching eastern parts of the Andaman Sea. Friday, they headed west of the Andaman and Nicobar islands near the Bay of Bengal.
There are more than 500 islands in that chain, many of which are richly forested and uninhabited.