A military transport aircraft crashed in the Belgorod region near the Ukrainian border on Wednesday, has left people with more questions than answers.
All 74 passengers on board were dead, according to Russian authorities.
The initial photographs of the debris on the ground are inconclusive; one video captures the plane's final seconds as it hurtles towards Earth before exploding in a massive blaze.
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However, Russian authorities claim that Ukrainian missiles were to blame, killing 65 of their own prisoners of war, as well as six crew members and three Russian servicemen on board the Ilyushin Il-76.
The Russian Defence Ministry stated that the plane was destroyed by an anti-aircraft missile system positioned in the Liptsy area of Ukraine's Kharkiv region, around 50 miles (80 kilometers) from where it crashed. It stated that radar systems had identified the rockets.
The Defence Ministry also stated that "the Ukrainian leadership knew very well that, according to established practice, today Ukrainian military personnel would be transported by military transport aircraft to the Belgorod airfield for exchange" at the Kolotilovka checkpoint on Russia's border with the Ukrainian region of Sumy.
In response, Ukraine's military command stated that Russian military aircraft approaching Belgorod were valid targets but did not acknowledge firing on a Russian transport jet.
Most Ukrainian ground-to-air missile weapons would be unable to reach the accident site from Liptsy, which is 50 miles away. A Ukrainian defense intelligence official confirmed that a prisoner exchange was scheduled for Wednesday but denied knowing the logistics of the Russian side of the transfer. Another Ukrainian military source was quoted as saying the jet was carrying Russian missiles, not captives.
So one question is if the Ukrainians were aware of the schedule and route of the plane that the Russians claim was transporting prisoners to the location of the exchange and whether that intelligence was sent to front-line soldiers across the border from Belgorod.