Missing plane: Malaysian PM stopped short of saying it was a hijack

Najib's statement confirmed growing speculation that the disappearance of the plane was not accidental as the probe will now bring flight's crew and passengers under scrutiny

Malaysian investigators suspect that the communication system in the missing aircraft was deliberately disabled and its transponder switched off before the plane veered from its path and flew for more than seven hours.

Prime Minister Najib Razak, who appeared before the media for the first time after a Malaysia Airlines flight with 239 people on board went missing without a trace on Saturday, stopped short of saying it was a hijack.

"We are still investigating all possibilities as to what caused MH370 to deviate," he said.

Najib's statement confirmed growing speculation that the disappearance of the plane, which took off from here to Beijing, was not accidental as the probe will now bring under scrutiny the flight's crew and passengers.

Shortly after the Prime Minister's statement, police went to the house of Captain Zaharie Ahmad Shah, the pilot of the missing flight. Two police officers went to 53-year-old Capt Zaharie's house in the suburb of Shah Alam here, officials said, without further elaborating.

"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.

He 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.

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.