The missile that downed a Malaysia Airlines flight over eastern Ukraine in 2014 belonged to a Russian brigade, international investigators say, According to the BBC.
For the first time, the Dutch-led team said the missile had come from a unit based in western Russia.
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 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 restated the JIT's conclusion that the plane had been destroyed by a Russian-made Buk missile, adding that it had been supplied by the country's 53rd anti-aircraft brigade in Kursk.
At a news conference in the Dutch city of Utrecht, the investigators also showed social media pictures which they said traced the route the missile convoy had taken to reach eastern Ukraine.
