Ukrainian Verkhovna Rada Human Rights Commissioner Liudmyla Denysova has asked Russian presidential Human Rights Commissioner Tatyana Moskalkova to help determine the whereabouts of Ukrainian citizens Volodymyr Dudka and Oleksiy Besarabov, who were convicted in Crimea earlier this year.

"The whereabouts of Ukrainian citizens Volodymyr Dudka and Oleksiy Besarabov are currently unknown," Denysova said on Facebook on Tuesday.

"I urged Russian Human Rights Commissioner Tatyana Moskalkova to take measures to determine the whereabouts of Volodymyr Dudka and Oleksiy Besarabov to inform their relatives and lawyers," she said.

"According to their relatives and lawyers, the Ukrainians were taken away from a penitentiary in the temporarily occupied Crimea at the end of September, and it is unknown where they are now," Denysova said.

Dudka and Besarabov were detained in Crimea on charges of subversive activities in 2016. A Russian court sentenced them to 14 years in a high-security penitentiary in April 2019. The Russian Supreme Court is to hear an appeal against their conviction on October 15.