The Kremlin spokesman Dmitry Peskov said there was no official decree on Vladislav Surkov's resignation and that there had been no change in policy
The deal is a major breakthrough for both countries, which have been seeking to resolve disputes over Ukraine's eastern Donbass region and the Crimea peninsula, which Russia annexed in 2014
The trade involved some of the highest-profile prisoners caught up in a bitter standoff between Ukraine and Russia
The conflict between Russian-backed separatist rebels and Ukrainian government troops has killed more than 9,500 people