The Joint Investigation Team (JIT) image shows a "Venturi", which emits propellant gases, like a car exhaust, according to BBC.
Dutch prosecutors want more information from Russia about the Buk, which they say killed 298 people aboard Malaysia Airlines Flight MH17 in July 2014.
The West and Ukraine say Russian-backed rebels fired the Buk missile.
Read alsoMH17 probe at "very advanced stage": investigatorsRussia argues that Ukrainian forces downed MH17. The Boeing 777, en route from Amsterdam to Kuala Lumpur, crashed in rebel-held territory.
The JIT interim report explains the progress of the criminal inquiry. The experts are studying a mass of tiny fragments retrieved from the crash site.
UNIAN memo. Boeing 777 of Malaysia Airlines flight MH17 from Amsterdam to Kuala Lumpur was shot down July 17, 2014 from the skies over Donetsk region with a surface-air Buk missile system No. 332 of the Russian 53rd air defense missile brigade based in Kursk region.
All 298 people on board were killed in a crash. The passengers were citizens of 10 countries. The majority of victims (196 people) were the citizens of the Netherlands. Among the dead were also 27 Australians.
October 13, 2015 Chairman of the Security Council of the Netherlands Tjibbe Joustra unveiled a report on the investigation into the MH17 disaster, which indicated that the plane was shot down by a Buk missile.
