"It was a completely a burger crowd, " said Ms. Mansuri, using a slang term for the affluent, middle-class voters who tend to support PTI.

WSJ: Karachi Beset by Political Strife

Ms. Mansuri said the staff finally allowed people to begin voting at 12.30pm, four-and-a-half hours late, but by then many had already left out of frustration.

WSJ: Karachi Beset by Political Strife

Anam Mansuri, one voter there, said that election officials at Neelumm Public School near the upscale Zamzama market inked peoples' fingers Saturday morning, a precaution to prevent double voting.

WSJ: Karachi Beset by Political Strife