Internet users are circulating a video that appears to show members of Egypt's army assaulting an older female activist called Khadiga al-Hennawy.
Hennawy was near the cabinet building on Qasr al-Aini Street on Friday when clashes erupted between protesters and security forces.
In the video, two officers are seen dragging Hennawy by the hair. One lets go of her hair to kick her, before other officers join in, beating her with batons and dragging her out of view.
Protesters in Tahrir Square and those staging a sit-in outside the cabinet building call Hennawy the “mother of revolutionaries” because she has taken part in several protests against the ruling Supreme Council of the Armed Forces. She also allowed activists to meet in her apartment to escape the eyes of security services.
This is one of several videos and photographs depicting scenes of male and female protesters being violently beaten by security forces. Activists say that members of the army have confiscated dozens of cameras documenting such attacks.
At least eight people have died and hundreds have been injured in the clashes so far.