The missile that downed a Malaysia Airlines flight over eastern Ukraine in 2014 belonged to a Russian brigade, international investigators say.
For the first time, the Dutch-led team said the missile came from a Russian brigade based in the city of Kursk.
All 298 people on board the Boeing 777 died when it broke apart in mid-air flying from Amsterdam to Kuala Lumpur.
It was hit by a BUK missile fired from rebel-held territory in Ukraine. Russia says none of its weapons was used.
But on Thursday Wilbert Paulissen, a Dutch official from the Joint Investigation Team (JIT), told reporters: “All the vehicles in a convoy carrying the missile were part of the Russian armed forces.”
He said investigators had traced the convoy to Russia’s 53rd brigade.
The incident occurred at the height of the conflict between government troops and pro-Russian separatists.
In October 2015 the Dutch Safety Board said the plane had been hit by a Russian-made Buk missile.
September 2016, the JIT – which includes officials from the Netherlands, Australia, Belgium, Malaysia and Ukraine – reached a similar conclusion in a preliminary report.
In response, Kremlin spokesman Dmitry Peskov told the BBC: “We cannot accept as final truth of what they say. I bet you haven’t seen any proof.”