MH370 disappearance still a mystery 2 years on

Investigators probing what happened to flight MH370 said Tuesday the cause of the plane's disappearance remained a mystery as the second anniversary passed with devastated next-of-kin still grasping for answers.

The Malaysia-led international team of aviation experts set up to investigate issued an annual progress report but the brief statement had no new insights on what caused the Malaysia Airlines jet to vanish.

"To date, the MH370 wreckage has still not been found despite the continuing search in the south Indian Ocean," it said.

It was the second straight year that the team of investigators, which includes representatives from the US National Transportation Safety Board (NTSB) and its counterparts from several other countries, had nothing to offer.

Malaysia and Australia, however, said they remained optimistic that the painstaking search for an Indian Ocean crash site will find something that could lead to the recovery of flight data recorders and eventually reveal what caused MH370's disappearance.

"The current search operation is expected to be completed later this year, and we remain hopeful that MH370 will be found," Malaysian Prime Minister Najib Razak said in a statement. 

The jet vanished on March 8, 2014 en route from Kuala Lumpur to Beijing with 239 passengers and crew onboard, mostly Chinese and Malaysians.

Authorities believe the Boeing 777 detoured to the remote southern Indian Ocean and then plunged into the treacherous waters.

A wing fragment confirmed to be from MH370 was found on an island thousands of kilometres (miles) from the search area last year, the first proof that the plane indeed went down.

The three nations have already indicated they will end the biggest and most expensive search effort in history if its high-tech scanning of a designated swathe of seafloor expected to be finished in a few months comes up empty.