The main target appears to have been an airplane that recently arrived from the United States. So it starts….
Karachi is an important port and on the path of the land based logistics chain supporting the NATO efforts in Afghanistan.
10,000 containers of materials destined for Afghnistan have been held up by the Pakistani government since the beginning of the year, causing much of the food inside to rot
http://tribune.com.pk/story/142410/afghan-transit-trade-resolving-the-bottleneck/