"About 740 people have been the victims of violent shootings in the last five months," Zohra Yusuf, chair of the Human Rights Commission of Pakistan (HRCP), told AFP.

The HRCP said last year a total of 1,715 people were killed in violent flare-ups in the city, which is Pakistan's biggest with an estimated population of 17 million.

The attacks often lead to punishing financial losses for Pakistan's economy as swathes of Karachi go into lockdown, with residents fleeing the violence and shops and markets closing.

"People are being killed with impunity by various ethnic groups while the government, it seems, has little control to put an end to it," Yusuf said.

The figures include the assassination of 107 political activists, while the rest of the victims were people with no political affiliations, HRCP said.

Much of the violence has been blamed on tensions between supporters of the Muttahida Qaumi Movement (MQM) and the Awami National Party (ANP).

NATO and the United States used Karachi to ship supplies for their war effort in landlocked Afghanistan, but Islamabad shut down the overland cross-border route after US air strikes killed 24 Pakistani soldiers last November.