Shakil Ahmed who was a candidate for PS-95 was among the three killed during an exchange of fire between two groups in Landhi-6.
Ahmed was a businessman and an independent candidate for the assembly in southern province Sindh but was supported by a faction of the Muttahida Qaumi Movement (MQM), the main party which controls Karachi, the Sindh capital.
“We have received three dead bodies, including that of Shakil Ahmed,” said Doctor Semi Jamali, head of the emergency department at Jinnah Hospital.
Khalid Hamid, spokesman for the MQM faction to which Ahmed was aligned, confirmed his death.
“Unknown gunmen opened fire on Shakil Ahmed and he along with two other supporters were killed on the spot. They were in the Landhi area of Karachi for an election meeting,” he said.
The faction defected from MQM in 1992 and has a bitter rivalry with the party, one of the main secular coalition partners in the outgoing federal government.
There was no immediate claim of responsibility for the hooting.
Attacks on politicians and political parties have now killed 127 people since mid-April.
Human Rights Commission of Pakistan has called the elections the most violent in the country’s history.