Ukrainian political prisoner Oleh Sentsov wrote a will regarding his artwork, his cousin Natalia Kaplan wrote on Facebook.

"He wrote a will regarding his artwork in the event of his death, and this is very frightening," the report said.

Kaplan also published an excerpt from Sentsov's letter, where he says he does not believe in returning to Ukraine.

Despite this, he says he is not going to surrender and stop the hunger strike.

"I don't believe anymore that I will soon be released and we will all live happily in Kyiv ever after, as well as many other things, but this does not mean that I have become a mess or that I'm about to quit [apparently, a hunger strike]. Anyway, I'm not giving up, I just don't believe in happy ending to this whole story," reads Sentsov's letter.

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Also, the Ukrainian film director wrote he had hypoxia - a lack of oxygen in body organs, "mostly in the heart and brain."

"My head is foggy, everything is spinning, my body, head and limbs are getting numb. The circulatory system does not cope at all with the oxygen supply. See how advanced I've become in medicine?" wrote the political prisoner.

As UNIAN reported earlier, Sentsov was arrested in Russian-occupied Crimea in spring 2014 and in August 2015 he was sentenced to 20 years in prison following an unfair trial where he faced "terrorism" charges stemming from his opposition to Russia's occupation of Crimea.

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He has been serving his term in a penal colony in the town of Labytnangi, Russia's Yamal.

He went on hunger strike on May 14, demanding that Russia free all Ukrainian political prisoners.

Sentsov's cousin, Moscow-based journalist Natalya Kaplan says his condition is critical and things are "catastrophically bad."