Pakistan's main commercial hub is being plagued by a fresh spate of deadly violence.
Officials in Karachi Saturday blamed unidentified gunmen for the shooting deaths of 17 people over the past three days, including a television journalist.
The southern port city has long been plagued by political and ethnic violence, which has fueled growing tensions between its two main political parties, the Muttahida Qaumi Movement and the Awami National Party.
Also Saturday, Pakistan officials said gunmen set fire to at least 18 tanker trucks carrying fuel oil to U.S. and NATO troops in neighboring Afghanistan.
They said the early morning attack in Baluchistan province injured at least one person.
The Pakistani Taliban claimed responsibility for the attack. Spokesman Azam Tariq told news agencies the Pakistani Taliban would continue to attack the convoys until they stop operating.
Islamic militants have been linked to previous attacks on tankers traveling between Afghanistan and Pakistan in the past.
In November, suspected militants were blamed for burning fuel trucks bound for NATO troops in Nagarhar province in Afghanistan.
Some information for this report was provided by AP, AFP and Reuters.