The woman, Shepark Shajarizadeh, 42, made the claims in a video posted to social media on July 10. On her personal website she wrote that she was imprisoned for "opposing the compulsory hijab" and "waving a white flag of peace in the street."
Her protest was part of a wider movement that resulted in the arrest of 35 people in Iran between December 2017 and February 2018, according to Amnesty International (media reports place the number arrested at 29). The women were arrested for removing their head coverings as a part of the "White Wednesdays" protest movement.
Shajarizadeh's lawyer, Nasrin Sotoudeh, told Amnesty International that she was placed in solitary confinement in a prison in Tehran and was beaten. Shajarizadeh was released on bail in late April. In June, Sotoudeh was reportedly arrested.
US officials egged on the protest in January, with US President Donald Trump tweeting a pledge to provide "great support from the United States," and US Ambassador to the United Nations Nikki Haley stating that "All freedom-loving people must stand with their cause," at a press conference on January 2.
The day before Haley's remarks, the Russian Foreign Ministry warned of "external interference" in Iran during the unrest.
The Iranian government has not commented on Shajarizadeh's claims.