Seems to be Air Blue, according to AP.
This earlier take
0633 28JUL10
ISLAMABAD (AP) Police say a passenger plane has crashed into the hills in Pakistan's capital.
It was unclear how many people were on board.
Officials at first thought it was a small plane. But police official Mohammed Saeed said later Wednesday morning that "it seems that it is a bigger tragedy" and that the aircraft was a passenger plan and may be larger than previously thought.
The accident occurred in the Margalla Hills in Islamabad on a rainy morning. Rescue workers were heading to the scene, but the roads were difficult.