By The Straits Times Malaysia Bureau

KUALA LUMPUR - There is a "high degree of certainty" that the data reporting system of Malaysia Airlines MH370 was disabled just before it reached the east coast of peninsular Malaysia, Prime Minister Najib Razak said on Saturday.

But he reiterated that the authorities are still investigating the possiblilty of a hijacking and what caused the plane to deviate.

"Based on new satellite information, we can say with a high degree of certainty that the Aircraft Communications Addressing and Reporting System (ACARS) was disabled just before the aircraft reached the East coast of peninsular Malaysia. Shortly afterwards, near the border between Malaysian and Vietnamese air traffic control, the aircraft's transponder was switched off," Mr Najib told a press conference.

He said the movements of the aircraft were consistent with deliberate action by someone on the plane.

He added that investigators are now refocusing their investigation on the crew and passengers.

He also said the search in the South China Sea has ended, adding that "the search has entered a new phase".

"We hope this new information brings us one step closer to finding the plane," Mr Najib said.

Mr Najib told the press conference that Malaysia has put national security second to the search for the missing Malaysia Airlines flight MH370.

Malaysia understands the desperate need for information but it can only release information that has been corroborated, he said.

"It has been an excruciating time for the families of those on board," Mr Najib said.

The fate of Malaysian Airlines Flight MH370, and the 239 passengers and crew aboard, has been shrouded in mystery since it vanished off Malaysia's east coast less than an hour into a March 8 scheduled flight fromKuala Lumpur to Beijing.