"While the ongoing search is divided into two massive areas, the data that the investigating team is collating is leading us more towards the north," sources said.
Prime Minister Najib Razak last week said authorities are 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.
Officials involved in the multi-national investigation said the probe would also focus on regions with disused airports equipped with long runways.
"There are two likely possibilities - either the plane landed somewhere and the engine was shut down or it crashed."
"As soon as the first country comes up with evidence of the flight's position after its last confirmed position (320km northwest of Penang), we will be able to refine the search and better determine its possible location," the officials said.
The mystery of the missing plane from Kuala Lumpur to Beijing since March 8 continued to baffle aviation and security authorities who have not succeeded in tracking the aircraft despite deploying hi-tech radar and other gadgets.
Malaysian police have refocused the probe on the crew, passengers and ground staff based on "new leads" that the plane was deliberately disabled and its transponder switched off before the plane veered from its path.
