"The Ministry of Foreign Affairs is checking information about O. Sentsov's transfer. We again demand the release of the Ukrainian political prisoner. #FreeSentsov," Betsa wrote on Twitter on September 8, 2017.

Read alsoSentsov wins Freedom to Write AwardAs UNIAN reported, the Russian human rights activist and journalist Zoya Svetova did not rule out that Sentsov, who was serving a sentence in penal colony No. 1 in Yakutsk, was transferred to a high-security prison in Irkutsk.

Sentsov was detained by the Russian FSB Security Service in Russian-occupied Crimea in 2014 together with activist Oleksandr Kolchenko. They were brought to Russia and tried in a trumped-up case on charges of organizing acts of terror and arson on the peninsula.

Read alsoUkraine activists mark two years since filmmaker Sentsov's conviction in Russia – mediaOn August 25, 2015, Sentsov and Kolchenko were sentenced to 20 years' and 10 years' imprisonment prison, respectively.

On October 21, 2016, Russia refused to extradite the two Ukrainians to Ukraine, claiming they had automatically acquired Russian citizenship after the annexation of Crimea.