Since the mid-2000s , the United States has been carrying out targeted killings of Al-Qaeda militants in Yemen , although the U.S. government generally does not confirm involvement in specific attacks conducted by unmanned aerial vehicles as a matter of policy . The Bureau of Investigative Journalism documented 415 strikes in Pakistan and Yemen by 2015 since the September 11 attacks , and according to the organization 's estimates , between 423 and 962 deaths are believed to have been civilians . However , Michael Morell , former deputy director of the CIA , affirmed that the numbers were significantly lower
September 11 attacks
September 11 attacks
Yemeni Civil War (2015–present)