With Russia's release of Ukrainian military pilot Nadia Savchenko, who returned to a hero's welcome in Kyiv, attention now shifts to the fate of other Ukrainians jailed in Russia on charges their supporters say are dubious.
At least 12 other Ukrainians remain in Russian prisons on convictions that have been condemned by the Ukrainian and Western governments and some international rights groups.
The most prominent of the prisoners is filmmaker Oleh Sentsov, whom Russian prosecutors have accused of plotting sabotage and terrorist attacks around Crimea in the weeks after Russia's annexation of the Ukrainian peninsula in March 2014.
Prosecutors built their case against Sentsov and another activist, Oleksandr Kolchenko, largely on the testimony of another Ukrainian man, Hennadiy Afanasyev -- but Afanasyev later recanted and said he was tortured into testifying against the two.
A court in the southern Russian city of Rostov-on-Don convicted Sentsov and Kolchenko in August and sentenced them to 20 and 10 years in prison, respectively.
Afanasyev was sentenced to seven years in prison.
Last month, Moscow indicated it was considering freeing the three men when the Justice Ministry asked the Federal Penitentiary Service to prepare documents for their transfer back to Ukraine.
However, the ministry said, any final decision to hand them over would be made by Russian courts.
Speaking on May 25 after welcoming Savchenko to Kyiv, Ukrainian President Petro Poroshenko said he expected Afanasyev and another Ukrainian, Yuriy Soloshenko, to also be released soon.
"This is just the first step because what will follow this, and I can already speak about this, will be the freeing of Soloshenko, Afanasyev, who are in very grave states of health," Poroshenko was quoted by news agencies as saying.
Soloshenko was convicted by a Moscow court of espionage after Russia's main security agency accused him of trying to buy secret components for an air-defense missile system used in both Russia and Ukraine.
Notably, Poroshenko did not appear to make specific reference to Sentsov or Kolchenko in his remarks.
Sentsov's defense lawyer, Mark Feigin, did not immediately respond to phone calls and text messages seeking comment from RFE/RL.
In February, Feigin said his client had been transferred to a prison facility in the Siberian region of Yakutia, thousands of miles east of Moscow. Feigin called the move "revenge for disobedience."