Violence broke out Saturday night when gunmen opened fire in several parts of the southern Pakistani city of 18 million ahead of the vote. At least 29 people have been killed since then, police said.

The election was being held to replace lawmaker Raza Haider, a member of Karachi's dominant Muttahida Qaumi Movement (MQM) whose killing by gunmen two months ago triggered violence that resulted in 100 deaths in a single week.

The MQM accused its rival, the ethnic Pashtun-based Awami National Party (ANP), of carrying out the attacks and killing some of its members. The ANP, which had boycotted the polls over rigging fears, denied the allegations.

Reuters