The Wall Street Journal reported the details.
The media outlet noted that this exchange was more complicated in terms of arrangements than the Russian-American exchange of pilot Konstantin Yaroshenko for Marine Trevor Reed.
According to The Wall Street Journal, the two sides were reluctant to start negotiations on the exchange. Ukraine said that it did not trust the Russian side and demanded the identification of the military held in Russian captivity.
Eventually the exchange took place after the head of Ukraine's military intelligence, Kyrylo Budanov, went on board with the Ukrainians, took their photos and sent them to Kyiv. The flight with 10 foreigners - combatants on the side of the Ukrainian Armed Forces - was accompanied by Russian businessman Roman Abramovich.
Ukraine exchanged Viktor Medvedchuk for 215 Ukrainian servicemen. In addition, Russia returned 56 of its servicemen from Ukrainian captivity.