Yes, I am aware of Blackwater Security company (now called Xe in Pakistan), their main job is to protect Americans. Their mischief action is happend, not really army, just mercenary security. They lost their job in Iraq, not longer in Iraq. and US court ordered them to face charges, there will be witnessed against this company. Blackwater securities (protecting American Embassy) are risk in Pakistan, we know it. Don't worry.
You will be disgusted to know, his Blackwater founder Prince, see here Youtube
Also see here
-Benazir Bhutto requested Blackwater security before election but Musharraf rejected her for sake of Pakistan security.