Russia and Ukraine exchanged 205 prisoners of war each on Friday, marking the first phase of a larger swap announced by US President Donald Trump.
The Russian defense ministry said 205 Russian servicemen were returned from Ukrainian-controlled territory in exchange for 205 Ukrainian prisoners of war.
Ukrainian President Volodymyr Zelenskyy said most of the Ukrainians released had been in Russian captivity since 2022.
Trump had announced last week that the two sides would carry out a mutual swap of 1,000 prisoners as part of a three-day US-brokered ceasefire covering Russia's May 9 parade.
Both sides have accused each other of violating the truce, and Ukraine reported that Russia intensified strikes on civilians after the ceasefire expired, killing at least 24 in an air barrage on Kyiv on Thursday.
Zelenskyy posted pictures of the freed Ukrainians wrapped in national blue-and-yellow flags, smiling and embracing.
He said they included troops who fought in the battle for Mariupol's steelworks Azovtsal and those who defended Chernobyl.
POW swaps remain one of the few areas of cooperation between the two sides since the war began in February 2022.
Russia said its troops were brought to Belarus for medical and psychological assistance, and that the United Arab Emirates provided humanitarian support.