Pakistani police say at least 12 people have been killed in two days of violence in the southern city of Karachi. They said the killings appeared to be the result of targeted attacks by rival ethnic and political groups. <br/><br/>The latest spate of killings started when ethnic Pashtun activists working for the Awami National Party (ANP) were attacked by unknown gunmen on Friday. The attack was followed by shootings across the Pashtun-dominated Orangi district, in western Karachi. <br/> Police said sporadic gunfire is still continuing in parts of Karachi. <br/><br/>The Karachi chief of the ANP, Shahid Syed, blamed activists loyal to the Muttahida Quami Movement (MQM) for the attack. The MQM, which represents the city's majority Urdu-speaking community, denied the allegations.