Ukrainian President Petro Poroshenko has urged Oleh Sentsov, the Ukrainian filmmaker who was sentenced to 20 years in prison in Russia, to hold on and keep his spirits up, adding that the organizers of his trial will appear before court themselves.

"I agree with Sentsov's words, the occupants' court can't be just by definition. Hold on, Oleh. The time will come and those who organized your trial will appear before court themselves!" Poroshenko said in a statement posted on his social media accounts on Tuesday.