The Kremlin has said Russian President Vladimir Putin and Ukrainian leader Petro Poroshenko discussed a possible exchange of prisoners.
"Special attention has been dedicated to humanitarian issues including an exchange of people being held" by the two sides, the Kremlin said in a statement on June 9 following the phone conversation by the two leaders.
The Ukrainian president's office said in a statement that the two leaders spoke by phone on June 9 and Poroshenko specifically requested the release of Ukrainian citizens being held in Russia who are on hunger strike.
Among those who Poroshenko urged Moscow to release was Oleh Sentsov, a Ukrainian filmmaker who is on hunger strike in a Russian prison in far-northern Yamalo-Nenets Autonomous Region.
Sentsov has been on hunger strike since May 14, demanding that Russia release of 64 Ukrainian citizens he considers political prisoners.
Sentsov was arrested in Crimea in 2014, after Russia seized the Ukrainian region. A Russian court in 2015 convicted him of planning to commit terrorist acts. He denies the accusations.