International and Dutch investigators are probing "several parts, possibly originating from a BUK surface-air-missile system," said a joint statement from prosecutors and the Dutch Safety Board (OVV).
"These parts have been secured during a previous recovery-mission in eastern Ukraine and are in possession of the criminal investigation team MH17 and the Dutch Safety Board," it said.
Flight MH17 was shot down on July 17 last year, killing all 298 people on board during heavy fighting between Kiev's armed forces and pro-Russian separatists.
Russia and the rebels deny any responsibility and point the finger at Ukraine's military.
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Members of the Joint Investigation Team (JIT) comprising representatives from the Netherlands, Ukraine, Malaysia, Australia, Britain, the United States and Russia are currently meeting in The Hague to discuss a draft OVV report into what caused the crash.
The statement from the OVV and JIT said that the pieces being investigated "can possibly provide more information about who was involved in the crash of MH17."
Investigators stressed that "at present the conclusion cannot be drawn that there is a causal connection between the discovered parts and the crash of flight MH17."
Russia last month vetoed a bid at the United Nations Security Council to set up an international tribunal to try those behind the shooting down.
Countries involved in that bid are now looking at other means to carry out a prosecution, although no suspects have yet been publicly identified or detained.