Two years on from the disappearance of Malaysia Airlines flight MH370, the UN's aviation agency Tuesday announced new requirements in a bid to avoid a repeat of a mystery that has perplexed investigators.

The jet vanished on March 8, 2014 en route from Kuala Lumpur to Beijing with 239 passengers and crew onboard, mostly Chinese and Malaysians, leaving distraught relatives still grasping for answers.

On the somber anniversary, the council of the International Civil Aviation Organization (ICAO) in Montreal adopted new measures that require aircraft to have tracking devices that can transmit location information at least once a minute when in trouble, effectively providing real-time updates.

Other new measures, also brought in in response to the MH370 mystery, include extending the duration of cockpit voice recordings to 25 hours, considerably longer than the current norm.

The new requirements "will now greatly contribute to aviation's ability to ensure that similar disappearances never occur again," said Olumuyiwa Benard Aliu, president of the ICAO council.

The changes will take effect between now and 2021.

Separately, the Malaysia-led international team of aviation experts set up to investigate the plane's disappearance issued an annual progress report, but the brief statement had no new insights on what caused the jet to vanish.

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 kilometers from the search area last year, the first proof that the plane indeed went down.