Malaysian PM stops short of saying MH370 hijacked

But says communication systems on board the plane were deliberately switched off

Not ruling out a hijack, Malaysia today said the movement of the missing Flight MH370 with 239 people on board was "consistent with deliberate action by someone on plane".

Prime Minister Najib Razak said authorities are now trying to trace the plane across two possible corridors - in the north to the border of Kazakhstan and Turkmenistan, and a southern corridor from Indonesia to the southern Indian Ocean.

"Based on new satellite communication we can say with a high degree of certainty that the aircraft communication addressing system was disabled just before the aircraft reached the east coast of Malaysia," Najib told reporters here at a press conference.

He said the aircraft's transponder was switched off shortly afterwards when the plane was between the border of Malaysian and Vietnamese air traffic control.

"Radar data showed that from this point onwards a plane believed to be MH370 did turn back and turned back in a westerly direction before turning north west.

"These were deliberate actions of someone on plane," he said, but stopped short of saying the aircraft had been hijacked.

"The last satellite communication was at 8.11 am (local time) on March 8," he said, suggesting that the plane was in the air for 7.5 hours after it lost the control.

The plane had left Kuala lumpur for Beijing at 12:41 am and lost contact with civilian radar and hour later.

"Despite the media of reports hijacking, I am very clear we are still looking into all possibilities," he said.

The Prime Minister said that based on the raw satellite radar it could be confirmed that the aircraft which was spotted an hour after it vanished from the civilian radar and seen on the military's primary radar was indeed the missing Malaysian plane Boeing 777 Flight MH370.

Najib said they will refocus on investigation of crew and passengers.

"Clearly the search for MH370 has entered a new phase," he said. "We hope this new information brings us one step closer to finding the plane."

He said, "We are ending our operation in the South China Sea and reassessing the deployment of our assets."

There has been no trace of the plane nor any sign of wreckage despite a search by the navy and military aircraft of 14 countries across Southeast Asia that involve 43 ships and 58 aircraft.