MH17 The black box, comprising cockpit voice and data recordings, could help establish if MH17 was shot down and where the missile was fired from.

But international investigators could be too late as reports claim that one of the devices has been sent to Moscow, sparking fears of a possible cover-up.

The news service Interfax reported that rebel Russian separatist forces in Ukraine had already found the black box and agreed to give it to a Russian-run regional air safety authority.

It quoted First Deputy Prime Minister Andriy Purgin of the breakaway Donetsk Republic as saying that the box would be transferred to Moscow for examination.

"Of course, we most likely will give them to the Interstate Aviation Committee (IAC), to Moscow.

"They are highly qualified experts who will be able to accurately determine the cause of the disaster, even though it is so clear," he said.

However, there have been no credible image of the black box and the reports are yet to be confirmed.

Meanwhile, Reuters quoted witnesses at the crash site claiming that rescue workers had recovered the second flight recorder.

Information in the black box is vital to shed light on the MH17 tragedy as both Russia and Ukraine blame each other.

Soon after the incident, Ukranian security services released a recording of phone conversations which confirmed that the Russian-backed rebels had shot down the plane.

“Russia blames Ukraine. Ukraine blames Russian-backed separatists. We won't stop until we find out who is responsible for MH17,” Youth and Sports Minister Khairy Jamaluddin tweeted earlier today.

“I feel very, very strongly that the MH17 black box must not be examined by either Russia or Ukraine. It must be returned to Malaysia,” Khairy said.

While the prime minister of Donetsk had pledged expressed commitment to an impartial investigation and would allow foreign investigators to inspect the crash site, he has not spoken on the status of the black box.

Several world leaders, including US President Barack Obama, UN secretary-general Ban Ki-Moon and Malaysian Prime Minister Najib Abdul Razak have called for an impartial investigation and said evidence at the crash site should remain undisturbed.