Prisoner of the Mountains (1996) on Netflix

Vanya is a raw recruit in the Russian army, leaving behind his mother when sent to the Caucasus where Islamic separatists wage guerrilla war. Vanya's tank patrol is ambushed; he and a hard-bitten sergeant (Sacha) survive, kept alive because a village elder, Abdul Murat, wants to trade them for his son, a prisoner in a Russian stockade. The Russian commander lacks the nerve to make the exchange, so Murat has Vanya write to his mother, begging her to come and plead for the trade. Time is the enemy: Sacha seeks to escape, and the villagers urge Murat to execute the pair. Loyalties are complicated by their interactions with the mute jailer and with Murat's teenage daughter.