The accusation from Ukraine came just as the leader of the self-proclaimed Donetsk People's Republic Alexander Borodai said Sunday his people have found what looks like the so-called black boxes.
The intercepted recorded conversations, which Ukraine's security services said took place Friday evening, suggest that Moscow ordered rebels to seize the flight recorders before investigators from the Organization for Security and Cooperation in Europe could find them.
The OSCE has complained of limited access to the site.
"Moscow asks where the boxes are," said a commander a member of a rebel search crew, according to the recording.
"We need to find out quickly."
In another recording identified as an intercept, the commander stresses several times that the flight-data recorders, which investigators believe will contain vital information about what downed the passenger plane, "doesn't fall into the hands of strangers. All those who are coming – the OSCE and the rest."
In the recordings, Ukraine's security services identified the rebel commander as Alexander Khodakovsky, head of the separatist "Vostok" battalion of fighters.
Khodakovsky made at least three phone calls to rebels engaged in the search at the crash site Friday evening towards dusk.
An aide to Khodakovsky said he had not heard of the recordings, but denied that separatists were hindering the OSCE.
"We consider the black boxes to be very important to an objective investigation," said the aide, Alan Manaev, by telephone.
"We hope that the OSCE will find them."
He said the downing of the airline flight was arranged by the Ukrainian government to discredit rebels.
"Of course we want an objective investigation," he said.
On Sunday, the Donetsk People's Republic leader Borodai said the black boxes have been found and are now being stored in Donetsk.
He said he is ready to hand them over to the international aviation experts, but not to the Ukrainians.
"We are not tech experts, none of us have seen a black box. We suspect that the artifacts we've recovered are the black boxes," he said.
The so-called black boxes, which register the technical details of a flight, provide investigators a recording of the conversation in the cockpit, as well as details about the condition of the plane up to point the plane was downed.
Investigators should be able to rule out any apparent mechanical failure bringing down the plane and could potentially extrapolate where the missile struck the plane by assessing in what sequence onboard equipment failed.
The Boeing BA +1.40% 777, like all commercial jetliners, didn't carry the kind of high-tech military equipment needed to determine from where the missile was fired or what type of missile it was.
The Ukrainian security services have posted a host of intercepted conversations in recent days implicating rebels in the downing of the aircraft.
On Sunday, the U.S. embassy issued a statement saying that a number of the audio recordings had been evaluated by intelligence analysts who said they were authentic.
The embassy offered no immediate comment on the recordings issued Sunday.
In one recording Khodakovsky tells a subordinate member of a search crew "I have a task s – it is not my task. Our comrades from on high are very interested in the fate of the black boxes. What I mean is Moscow... make sure that everything that is found doesn't fall into the hands of strangers."
In another call about an hour later he talks to another member of the search crew who asks what the boxes look like, according to the recording.
The searcher says they found a box with a label indicating that it was a unit for satellite navigation, the recording indicates.
"Take it in any case - maybe they [the boxes] are concealed under something," Khodakovsky says, according to the recording.
In Sunday's statement, Borodai declined to say how many black boxes had been found and declined to disclose their color.
The black boxes are usually bright orange to be easily found in case of an accident.
Of the Ukrainian authorities, he said, "We don't trust them, as they may tamper with the devices, swap them and prevent investigation."
Source: The Wall Street Journal