Thirty workers of Imran Khan's Tehreek-e-Insaf party, including seven of his kin, were arrested in Islamabad on Thursday when they tried to stage a protest against the arrest of the cricketer-turned-politician and the imposition of emergency.
About 40 party leaders and workers, mostly women and including members of Khan's family, gathered at Barket Market for the protest.
A heavy police contingent posted in the area arrested 30 of them when they started shouting slogans.
Those arrested include Salomi Bukhari, the president of the Tehreek's Punjab unit, media advisor Nasim Zohra and information secretary Talat Naqvi.
Bukhari told reporters that the party's struggle for democracy would continue.
She also demanded the release of all political leaders and workers detained under the emergency declared by President Pervez Musharraf on November 3.
Khan was arrested on Wednesday when he emerged from hiding to join a student protest against the emergency and was charged under an anti-terror law for inciting unrest.
The former cricket captain, who was on the run to evade arrest since the emergency was imposed, was detained by members of the radical Islami Jamiat-e-Talaba, the student wing of the Jamaat-e-Islami, when he came to the Punjab University to address a protest.
Khan said he had been "betrayed" by members of the IJT who had acted in league with police.