British Ambassador to Ukraine Melinda Simmons has called on the Russian side to release a citizen of Ukraine, Crimean Emir-Usein Kuku, who has been in prison for five years.

"Kuku is just one of at least 109 Ukrainian political prisoners unjustly imprisoned by Russia. Like many others, he has been held held in inhuman conditions and denied medical care. This cannot continue. I call on Russia to release Kuku and all Ukrainian political prisoners immediately," Simmons wrote on Twitter on Thursday.

Member of the British Parliament Wendy Morton also called on to release Kuku. "A grim milestone today: Crimean Tatar human rights defender Emir-Usein Kuku marks five years in Russian detention after his politically motivated arrest in Crimea. Russia must end its persecution of Crimean Tatars and release Mr. Kuku at once," she wrote on Twitter.