Zahra Shahid Hussain, the vice-president of the party's chapter in Sindh, was shot by two unidentified men outside her home in Defence Phase IV late tonight. She died while being taken to a nearby hospital.
Hussain was a member of the party's central executive committee. The motive for the murder could not immediately be ascertained. The killers escaped on a motorcycle.
The shooting occurred hours before re-polling in some polling stations of a parliamentary constituency in Karachi.
The Election Commission ordered the re-polling following several days of protests by the Pakistan Tehrik-e-Insaf and other parties over rigging in the constituency during the May 11 polls.