Police have arrested Aleema Khan, the sister of Pakistan's jailed ex-prime minister Imran Khan, at her house in Lahore, a spokesperson from Khan's Pakistan Tehreek-e-Insaf party said on Sunday.
The arrest was made ahead of a planned protest march by Khan's party on September 27.
A notification issued by Lahore's district administration said she has been arrested and sent to jail for 30 days.
"According to intelligence reports, her presence at any public place will pose a grave threat to public safety," the district administration said.
Imran Khan's party has organised a march to Islamabad next week demanding his release.
Pakistan's Interior Minister Mohsin Naqvi said on Saturday that the government would do everything it could to stop the protest march.
A close aide to Khan, Zulfi Bukhari, described the arrest of Khan's sister as "absolutely despicable".
"The fear of the 27th protest is clearly taking its toll," Bukhari added.
Hurricane Isaias strengthens as it heads for US Gulf Coast
US suspends Microsoft, major IT firms from key green card programme
Intercepted missile debris damages kindergarten, clinic complex in Riyadh
India's 'Cockroach' movement says many members detained ahead of Delhi rally
Russian bomb kills 33 in street in east Ukraine stronghold
