Iran has arrested two prominent actresses who removed their headscarves in public to show support for the ongoing protest movement calling for freedom for women, sparked by the death of 22-year-old Mahsa Amini in custody last September.

According to multiple reports citing state media, Hengameh Ghaziani and Katayoun Riahi were detained after being summoned by prosecutors and are accused of collusion and acting against Iran’s authorities.

Ghaziani, an award-winner for 2008’s As Simple as That and 2012’s Days of Life, has been a vocal critic of the crackdown on protesters. She wrote in an Instagram message this weekend, “Maybe this will be my last post. From this moment on, whatever happens to me, know that as always, I am with Iranian people until my last breath.”

The accompanying video shows Ghaziani turning her back on camera and wrapping her uncovered hair into a ponytail, a gesture which has come to be symbolic of women preparing to protest.

The post remained up on Instagram following reports of her arrest. The Iranian authorities often force political detainees to remove content from their accounts.

(With inputs from agencies)