Question remains: Just what happened on Flight MH370?

It was yet another bizarre twist in an already puzzling saga.

Seventeen days after MH370 disappeared while flying from Kuala Lumpur to Beijing, Malaysian Prime Minister Najib Razak said last night that satellite data has confirmed that the plane ended its journey in the southern Indian Ocean. With no nearby landing sites, the Malaysia Airlines plane, which was carrying 239 crew members and passengers, is assumed lost with no survivors.

Aviation and air experts said it was strange for Datuk Seri Najib to make this announcement without offering any evidence.

However, he did say more details will be given today.

In the last few days, Australia has led a multinational search after satellite images confirmed that debris had been found about 2,500km south-west of Perth. The expectation was that Mr Najib would confirm the debris came from the Boeing 777-200ER jet.

But he did not, and his announcement has not shed any light either on what happened to the ill-fated flight and how it got to the southern Indian Ocean.

Mr Paul Yap, who heads Temasek Polytechnic's aviation course, said: "What he is saying is that the plane is in the southern corridor and that this is based on satellite data. But where is the proof and where is the debris?"

Mr Michael Daniel, a retired United States Federal Aviation Administration official, said: "You have the leader of a country making such a statement and offering condolences to the families so you would assume he is 100 per cent sure of the information he is getting from the satellite experts.

"But as far as the investigation goes, I don't necessarily see this as a game-changer. We still don't have real information on what happened... and we are still not able to rule out any of the theories that have surfaced to date."

The biggest questions are yet to be answered, experts believe.

What happened in the period of more than six hours from the time air traffic controllers lost contact with the plane to the time it stopped transmitting data captured by satellites? Did some major mechanical or other failure knock everyone out and keep the plane flying on autopilot?

The consensus is that this is highly unlikely.

If there was a problem with the aircraft, the captain or co-pilot would have been able to send a distress signal, which was not done.

In almost all major air mishaps that have occurred, the pilots always managed to call for help, experts said. They are generally in agreement that MH370 fell prey to a hostile takeover. "We still cannot rule out foul play," said one security expert who asked not to be named. "It's possible this was an ill-intentioned plot that somehow went wrong."

Mr Daniel added: "This has been and continues to be an unprecedented air accident.

"With the PM's announcement, the search has effectively been called off in the northern corridor but it should continue in the southern Indian Ocean. Getting to the debris and the black box is the only way we will find out what happened to MH370."

With less than two weeks to go before the battery in the black box stops, the clock is ticking.