Ukrainian filmmaker Oleh Sentsov who is serving time in a Russian penitentiary has refused to undergo a medical check under the supervision of doctors chosen by his family and lawyer, Russian Human Rights Commissioner Tatyana Moskalkova said in a program aired by the television channel 112.ua on Tuesday morning.

"We have offered, I have offered the administration of the penitentiary system to arrange an examination by doctors suggested by the lawyer or the family, so that they are trusted. He said he refused to meet with any doctors, he was strong, he would not give them any satisfaction, and he would be defending his stance till the end," Moskalkova said in Kyiv.

Sentsov "can stand and speak," she said.

"I do not see a lethal danger but I cannot help but worry because 40 days on a hunger strike is a very long period of time," Moskalkova said.

She added she was receiving daily reports about Sentsov's health from the human rights commissioner of the Yamal-Nenets Autonomous District, Anatoly Sak.

Moskalkova said she would visit Sentsov upon her return from Kyiv and would do so together with Ukrainian Human Rights Commissioner Liudmyla Denisova should the permission be granted.

"I will definitely visit him upon my return from Kyiv. If I am allowed to pay the visit together with Liudmyla Denisova, we will go there together," Moskalkova said.

Denisova has been in Russia since June 14. She has not had a chance to meet with any Ukrainian prisoners as of yet.