Fragments of a suspected Russian missile system have been found at the Flight MH17 crash site in Ukraine, investigators in the Netherlands say.
They say the parts, possibly from a Buk surface-to-air system, are “of particular interest” and could help show who was behind the crash.
But they say they have not proved their “causal connection” with the crash.
MH17 crashed on land held by Russian-backed rebels in July 2014, killing all 298 on board.
It had 283 passengers on board, including 80 children, and 15 crew members.
About two-thirds of those who died were Dutch nationals, with dozens of Malaysians and Australians among the rest.
Ukraine and many Western countries have accused pro-Russian rebels of shooting down the Malaysian Airlines plane, saying they could have used a Buk missile system supplied by Russia.
Russia and the rebels deny any responsibility and say the Ukrainian military was to blame.
How a missile could have brought down MH17
The Joint Investigation Team (JIT) said in a joint statement with the Dutch Safety Board that the parts had been “secured during a previous recovery mission in eastern Ukraine”.
“The parts are of particular interest to the criminal investigation as they can possibly provide more information about who was involved in the crash of MH17. For that reason the JIT further investigates the origin of these parts,” the statement said.
“At present the conclusion cannot be drawn that there is a causal connection between the discovered parts and the crash of flight MH17.”
The investigators would now enlist the help of weapons experts and forensic specialists to examine the parts, the statement added.
The JIT comprises representatives of the Netherlands, Ukraine, Belgium, Malaysia and Australia.
They are meeting in The Hague to discuss a draft report on the causes of the crash, the final version of which is expected to be published by the Dutch Safety Board in October.
The statement comes two weeks after Russia vetoed a draft resolution to set up an international tribunal into the disaster, triggering widespread outrage.
Moscow described the Malaysian initiative as “premature” and “counterproductive”.
The Boeing 777 was flying from Amsterdam to Kuala Lumpur when it was brought down on 17 July last year in Donetsk region.