The finding was revealed as a convoy of international inspectors, including Australian Federal Police officers, abandoned an attempt to reach the crash site for the second day running amid fierce fighting in the rebel-held area.
Data from the doomed airliner's black boxes was decrypted in Britain after being handed over to Malaysian officials by the pro-Russian rebels controlling the crash site.
Ukraine's National Security and Defence Council spokesman Andriy Lysenko said international investigators believed data from the flight recorders show "the reason for the destruction and crash of the plane was massive explosive decompression arising from multiple shrapnel perforations from a rocket explosion".
Surface-to-air missiles such as the Buk system widely believed to have shot the passenger jet down can explode near their targets, blasting a cloud of shrapnel into them.
Investigators leading the probe in the Netherlands, which lost 193 citizens in the air disaster, refused to confirm the latest information from Kiev, saying that they were "waiting to get a more complete idea of what happened".
Kiev and its Western allies, including Australia, have accused insurgents of shooting down the plane, killing all 298 people on board, including 38 Australian citizens and residents.
both the CVR and the FDR require the aircraft to provide their power source during normal operation... once power is removed from these devices, as would occur in a catastrophic event, recording ceases... concentrating on the CVR- the CVR records any/all communication of only the cockpit flight crew voices, and sounds generated from cockpit speakers overhead... the CVR mic would have recorded any/all comm. between the cockpit crew and the Ukr. ground station controller, i.e., course diversion, altitude change, for X amount of minutes depending on CVR type... this comm. between the aircraft and ground as recorded, in my view, holds the key... any anomaly, uttered or spoken of by the cockpit crew prior to the end event may be on the tape... here's hoping that the lab doing the analysis of these voice recordings has no hidden agenda and does release the entire transcript... but I'm not holding my breath here