Renowned women's activist Narges Mohammadi claims she was physically assaulted on Monday for not adhering to mandatory hijab in the presence of prison authorities.

Mohammadi, who has repeatedly spoken out against human rights violations in Iranian prisons, including "sexual harassment and abuse of women" in detention facilities, was sentenced to an additional year of punitive imprisonment on charges of "advocating against the system through issuing statements from inside the prison."

The most recent incident was reported on her Instagram account. Mohammadi has become famed for raising awareness to the systematic abuse of women in Iranian prisons and in a bid to silence her, the authorities often refer to her as insane.

In recent years, innumerable reports have surfaced about the torture of political detainees and ordinary prisoners under various charges in Iranian prisons. Iran's Me Too Movement has also reported that sexual violence and intimidation has become a standard weapon against women by the regime, both inside and outside prison, with thousands of Iranian women seeking the support of the group since the unrest of September.

Mohammadi has published several letters from inside prison in support of the Iranian people's revolutionary movement, condemning the suppression of students and protestors, advocating for the rights of the Baha'i community, and others.

Iran's prison organizations issued a statement Tuesday dismissing the allegations.