The United States has once again demanded that Russia release Ukrainian film director Oleh Sentsov, who was convicted by the Russian court for terrorist activities in Crimea.

"The United States is deeply concerned about his [Sentsov's] deteriorating health, and we renew our demand that Russia immediately release him and all Ukrainian citizens unlawfully imprisoned in Russia and on the Crimean peninsula," the State Department said in connection with the 100th day of the hunger strike of Oleh Sentsov.

The statement says that Washington "is alarmed about the prospect of another innocent person dying in Russian custody."

"We hope Russian authorities will release Sentsov to avoid such a tragedy, which would inevitably lead to calls for those officials responsible to be held to account," it says.