Pakistani rights activists have accused the police of brutality after they used force to break up a rally in support of a mixed sex road race in Lahore.
Police attack an Islamic activist protesting against the race
Nearly 30 people were briefly arrested on Saturday. A number were beaten before being taken away.
Those assaulted and arrested include prominent activist Asma Jehangir, and protesters from Islamic parties.
Police said the rights group Ms Jehangir leads had violated a ban on joint road races for men and women.
Authorities banned women from taking part in such races after Islamic activists attacked runners at an event last month.
The BBC's Zaffar Abbas in Islamabad says the police action in Lahore was unexpectedly harsh, and has sent a wave of shock and anger through Pakistan's liberal political and social groups.
According to one report, the policewomen who roughed up Ms Jehangir, chairwoman of the Human Rights Commission of Pakistan (HRCP), also used foul language and tore her clothes, before dumping her in a police van.
Other activists who were manhandled and detained included HRCP secretary general Iqbal Haider and prominent rights lawyer Hina Jilani. They were set free after several hours in custody.
An HRCP statement said by using brute force to prevent a peaceful attempt at drawing attention to violence against women, the authorities had demonstrated their anti-women bias and contempt for basic rights.
Ms Jehangir (wearing glasses) was forcibly taken away
It described the police action as the "true face of the state".
The statement went on to lament that such thuggish behaviour had increasingly become the norm - particularly in Lahore - as a means to prevent basic rights.
On her release, Ms Jehangir said the police action had exposed the government's claim that it was pursuing a policy of liberalism and tolerance.
"They do not want independent voices. They are a militaristic government, and they are a hard, dictatorial government," she told the BBC.