Malaysian authorities have released a preliminary report into the disappearance of flight MH370.

This comes as ongoing searching for the flight has so far failed to find any clue in the nearly 2-months since the plane disappeared.

Three possible flight-path maps have been released along with the recording of conversations between the flight and the Kuala Lumpur control tower.

MH370: DELIVERY MAS 370 GOOD MORNING. ATC: MAS 370 STANDBY AND MALAYSIA SIX IS CLEARED TO FRANKFURT VIA AGOSA ALPHA DEPARTURE SIX THOUSAND FEET SQUAWK TWO ONE ZERO SIX."

The audio shows communication prior to take off and MH370 signing off Malaysia's airspace, ending with the words, "Good night Malaysian 370".

The preliminary report confirms that military radar tracked a plane after takeoff in early March as it turned in a westerly direction across the Malaysian peninsula.

But the military took no further action because the plane was deemed "friendly".

The report does not explain why the flight was regarded as friendly even though its transponder was switched off by the time it turned back.

It also recommends that the U.N. body overseeing global aviation considers introducing a system for tracking commercial aircraft in real time.

The release of the report comes as Malaysia Airlines says that the continuing search and investigation will be a prolonged process.

The Airline also says it will compensate next-of-kin who are entitled to claim compensation.

Meanwhile, the Chinese Foreign Ministry says China will actively participate in the follow-up search operation.

The Ministry says China is ready to cooperate with Malaysia and Australia in the search effort and provide services to relatives of the passengers to protect their lawful interests.

Australia now plans to contract commercial companies to undertake a sonar search of the seabed northwest of the Australian city of Perth.

The process could take eight months or more.

Up to 26 countries have been involved in the search.

The Malaysian ailine flight mysteriously disappeared while headed to Beijing.

Some 239 people were onboard the plane, among them are some 150 Chinese passengers.