SYDNEY, Australia - A report into the search for Malaysia Airlines Flight 370 says the continuing mystery over the fate of the plane and the 239 people on board is "almost inconceivable."

But the Australian Transport Safety Bureau's report on the search, abandoned in January, concedes that authorities are no closer to knowing the reasons for the plane's disappearance, or its exact location. This is despite last year's narrowing of the plane's most likely resting place to a 25,000-square-kilometre patch of the southern Indian Ocean.

The ATSB expressed its "deepest sympathies" to families of the passengers and crew, saying it was "almost inconceivable and ... societally unacceptable" for the world to not know what became of the plane.

MH370 disappeared en route from Kuala Lumpur, Malaysia, to Beijing on March 8, 2014.