In a far more detailed description of military radar plotting than has been publicly revealed, two sources told Reuters an unidentified aircraft that investigators suspect was missing Flight MH370 appeared to be following a commonly used navigational route when it was last spotted early on Saturday, northwest of Malaysia.

That course - headed into the Andaman Sea and towards the Bay of Bengal in the Indian Ocean - could only have been set deliberately, either by flying the Boeing 777-200ER jet manually or by programming the auto-pilot.