- Malaysia and China mark a year without a clue to the tragedy
- Support group Voice 370 hosts "Day of Remembrance" in Kuala Lumpur
- Ships dragging sonar devices continue search of 60,000-s/km off western Australia
Families of the 239 people on board Malaysia Airlines Flight 370 are marking the anniversary of the plane's disappearance with a vow to never give up the search for wreckage and answers to the world's biggest aviation mystery.
Voice 370, a support group for the kin of those on board, hosted a Day of Remembrance at a mall in Kuala Lumpur on Sunday.
A report by an international investigative team released on Sunday raised no red flags relating to the crew or the aircraft's condition to indicate any cause for the disappearance.
But it said the 30-day battery powering the underwater locator beacon on the flight data recorder was due to expire in December 2012.
Although the battery on the plane's cockpit voice recorder was up-to-date, this could have contributed to the failure to find the plane, said Gerry Soejatman, a Jakarta-based aviation consultant.
Although no wreckage has been found, officials in Australia, Malaysia and China, the three countries leading the search effort, say they are still optimistic the passenger jet will be found in the southern Indian Ocean where they suspect it crashed after deviating from a flight to Beijing.
A year without a clue to the tragedy has frustrated the relatives.
"The lack of answers and definitive proof - such as aircraft wreckage - has made this more difficult to bear," Najib Razak, Malaysia's prime minster, said in a statement.
| 101 East: MH370 - The unending search
"Together with our international partners, we have followed the little evidence that exists. Malaysia remains committed to the search, and hopeful that MH370 will be found."
Wang Yi, the foreign minister of China, where most of the passengers came from, said his government will provide "all needed service to every next of kin" and help uphold their "legitimate and lawful rights and interests".
"A year has passed, the plane has not been located, but the search effort will continue," he said in Beijing. "Today must be a difficult day for the next of kin ... Our hearts are with you."
In late January, Malaysia's government formally declared Flight 370's disappearance an accident and said all 239 people on board were presumed dead.
The statement was meant to pave the way for compensation claims, but it angered many relatives who deemed it to be premature without any physical evidence of the crash.
Ships dragging sonar devices have so far scoured 44 percent of a 60,000sq km area off western Australia where investigators who analysed transmissions between the aircraft and a satellite believe the aircraft eventually crashed after deviating from its route, with its transponder and other equipment switched off.