Pakistani police fired tear gas and water cannons to disperse female-led protests in Islamabad on Thursday.
At least 200 people were arrested, including protest leader Mahrang Baloch, as they entered the capital.
Protesters have been marching across the country for weeks against alleged enforced disappearances of men in Balochistan province.
This was sparked by the death of a Baloch man whose relatives allege was shot dead while in police custody.
The march is "under attack by the Islamabad police," Ms Baloch said on X, formerly known as Twitter, at about 02:30 local time (21:30GMT).
The protesters were prevented from entering the Red Zone, which houses executive, judicial and legislative buildings in Islamabad, by police officers bearing batons and wearing protective head gear.
Videos posted on social media show chaotic scenes of officers bundling protestors into police vehicles. Many can be seen shouting and crying, while several are seated on the ground with visible wounds.