At least ten people were killed and 30 others injured when a blast went off near a polling station in Pakistan's southern port city of Karachi on Saturday morning, reported local Urdu TV channel Dawn.
Some of the injured were in critical condition, said sources with Jinnah Hospital in the city, which admitted the blast victims, adding a child was among the killed.
The blast also damaged six vehicles and eight shops, said local media.
According to the media reports, the blast took place at about 10:00 a.m. local time when a group of supporters of Awami National Party (ANP), a local political party which mainly represents the interests of the Pashtun from the country's northwest region, were gathering together near a polling station in the Quaidabad area of Karachi.
They gathered there to vote for ANP candidate Aman Ullah, said the reports.
Aman Ullah remained safe in the blast.
The bomb was hidden inside a car parked nearby the polling station and was detonated through a time device, said police.
No group has claimed responsibility for the attack yet.
Pakistan Taliban had threatened to attack the people voting for ANP as the party is against the militant group.
Saturday's blast in Karachi is the most deadly attack so far reported during the election day in the country.