Following the Minsk agreement of 12 February, the Ukranian government and the pro-Moscow rebel forces exchanged dozens of prisoners on Saturday.
Russia's War Against Ukraine
International Business Times: Prisoners’ swap strengthens Minsk ceasefire agreement

Ukrainian prisoners and militants of the self-proclaimed \"People's Republic of Donetsk\" stand prior to a prisoner exchange between Ukraine and pro-Russian rebels on December 26, 2014 in the eastern Ukrainian city of Yasinovataya, near Donetsk.