(CNN) -- Eighteen people were killed in Karachi since Sunday in what police are calling politically motivated target killings.
Twelve people were also wounded in the political infighting in the southern Pakistan city, Rafiq Gul, a Karachi police official said Tuesday.
Police say the violence is connected to last week's killing of a prominent politician.
Politician Imran Farooq of the Muttahida Quami Movement (MQM) was killed Thursday in London, a spokesman for his party told CNN.
The MQM, one of the largest parties in Pakistan, is part of President Asif Ali Zardari's ruling coalition.
The killing has sparked violent clashes between the MQM and member of the Awami National Party (ANP), police said.
For years, both parties have been engaged in bloody battles.
CNN's Reza Sayah and journalist Nasir Habib contributed to this report.