In different incidents of target killing and violence, activists of the major political parties Mutthaida-e-Qaumi Movement, Awami National Party and the Pakistan Peoples Party were killed by unidentified assailants.
Orangi Town was the worst hit with target killers gunning down six people in the town.
In North Karachi, assailants riding a motorcycle gunned down a lawyer of a notorious target killer, Ajmal Pahari, who is awaiting trial for his criminal activities.
Advocate Zia Aslam, who was also a senior member of the Sindh council of the ruling Pakistan Peoples Party was shot dead while he was returning home.
The lawyer was defending Pahari in a high-profile case as the latter is accused of carrying out around 100 target killings.
A senior member of the MQM, Shafiq Ajmeri, was also gunned down in front of his house in Orangi, sparking violence and protests in parts of the town where markets and shopping plazas closed down abruptly.
Police said in the wake of the killings protesters had burnt some vehicles and petrol pumps in Orangi town and some other parts of the city.
Karachi, Pakistan's largest city and financial hub, has been in the grip of violence since early this year with police and rescue officials confirming around 300 deaths of political activists, religious leaders and the common man in target killings in the city.