Oleg Sentsov was arrested last May in Simferopol, Crimea’s main city, by Russia’s FSB security service and charged with plotting and carrying out “terrorist attacks” after the region was annexed by Russia.

A spokeswoman for a military tribunal in the southern city of Rostov-on-Don told Interfax news agency that the trial will begin July 21 and that Sentsov’s preliminary detention has been extended to December.

Top film directors including Spain’s Pedro Almodovar and Britain’s Ken Loach have previously expressed concern for Sentsov in an open letter to Russian President Vladimir Putin.

Pro-Kiev Sentsov has reportedly been charged with creating a terrorist group, carrying out two attacks and plotting two more, as well as illegally acquiring explosives.

Sentsov denies the charges and Amnesty International says that the allegations are “fabricated”.

Sentsov, 38, lives in Crimea. He presented his first feature film, “Gamer”, about a computer-game obsessed teenager, at the Rotterdam Film Festival in 2012.