Russia said it’s in talks about a possible prisoner swap involving Ukrainian sailors that it detained last year, signaling a potential Kremlin concession to Ukraine’s new president, Volodymyr Zelenksiy, as he appeals for support in parliamentary elections.

“It’s being discussed — we’re thinking about it,” Russian Deputy Foreign Minister Grigory Karasin said Monday, the Interfax news service reported.

Russian President Vladimir Putin and Zelenskiy, a former TV comic who won a landslide election victory in April, discussed the 24 imprisoned sailors during the first phone call between the two leaders last week. Zelenskiy, a political novice, pledged to secure the release of the sailors in his first speech after he won. He’s now seeking to cement his grip on power by urging voters to support his nascent political party in early parliamentary elections on July 21, giving him a platform to push through promised radical changes.

The sailors have been in Russian custody since November when they and their vessels were seized during a naval clash in the Kerch Strait, off the coast of Crimea. Russia annexed Crimea from Ukraine in 2014. Ukraine won a legal victory in May when a United Nations tribunal ordered Russia to immediately release the captured ships and sailors. Russia argued the tribunal had no jurisdiction in the case.

A court in Moscow is due on Wednesday to consider a request from investigators to extend the custody period of the Ukrainian sailors for three months until October, according to Interfax.

The Ukrainian authorities have included the detained sailors in lists drawn up by both sides for a planned prisoner swap, the country’s human rights commissioner, Lyudmyla Denisova, said in Kiev Monday after meeting her Russian counterpart, Tatyana Moskalkova, Interfax reported.

Hearing Delayed

A Kiev court on Monday postponed until Friday its hearing into treason allegations against Kirill Vyshinsky, head of the Ukraine office of Russia’s state-run RIA Novosti news service, RIA reported. Vyshinsky faces up to 15 years in prison on charges of supporting Russian-backed separatists fighting in eastern Ukraine. He denies the charges.