Although Malaysian Prime Minister Najib Razak has announced that flight MH370 has crashed into the southern Indian Ocean, there are still a lot of unknowns surrounding the fate of the plane.

The conclusion the Malaysian authorities reached was based on an analysis of the Air Accidents Investigation Branch and Inmarsat using satellite imagery, Wu Peixin, an aviation expert in Beijing, told China Daily on Monday.

"However, as far as I know, no one outside the two organizations and the Malaysian government has seen solid evidence such as parts of the aircraft's debris," he said.