“For the time being, it would not be appropriate… to issue any official conclusions as to the aircraft’s flight path until a high amount of certainty and verification is achieved,” Air Force chief General Rodzali Daud said in a statement.
“However all ongoing search operations are at the moment being conducted to cover all possible areas where the aircraft could have gone down in order to ensure no possibility is overlooked.”
Authorities have so far revealed no details on radar data they said indicated a possible “turn-back”.
The search zone shift is the latest twist in the mystery surrounding the plane. On Tuesday, Malaysian authorities said two men travelling on stolen passports appear to be Iranian illegal immigrants — easing fears of terrorism.
Malaysia’s national police chief Khalid Abu Bakar has said his officers are not ruling anything out but were now focusing on a possible hijacking, sabotage, or psychological or personal problems among passengers or crew.
The search operation grew to involve 42 ships and 35 aircraft as of Tuesday, from Southeast Asian countries, Australia, China, New Zealand and the United States.
China, which had 153 of its nationals on board the plane, said it would harness 10 satellites equipped with high-resolution imaging to help in the search.
Boeing said it was joining a US government team to try to unravel the mystery of what happened to its 777-200 plane.