Russia accused the United States of trying to break the spirit in jail of Maria Butina, a woman U.S. authorities say is a Russian government agent, and complained she was being subjected to "borderline torture."

Butina, a 29-year-old gun rights advocate living in Washington, D.C., was arrested in July and has been accused of acting as a Russian government agent while developing ties with American citizens and infiltrating political groups.

Butina, who pleaded not guilty, was detained without bail pending trial after prosecutors presented evidence suggesting she had connections to Russian intelligence operatives and was being funded by Russian oligarchs.