Washington, May 28 (RHC)-- Leaders of the U.S. Senate Armed Services Committee have called on the Pentagon chief to make arrangements for the proper training of assassination drone pilots. Committee Chairman John McCain and ranking member Jack Reed notified Defense Secretary Ash Carter about the issue on Wednesday, after a report from the Government Accountability Office (GAO) revealed this month that the Pentagon was facing "challenges" to train drone pilots.

In a letter to the Pentagon chief, they wrote: "We are disturbed that the Department of Defense has no standardized training program for UAS [unmanned aerial system] pilots and personnel.""

Drone pilots may not be receiving the training they required to operate their aircraft, the GAO, which acts as Congress's investigative arm, said in a report published on May 14th. "The U.S. Army and the Air Force face challenges ensuring that the pilots who remotely operate their unmanned aerial systems (UAS) complete their required training," it added.

Since 2001, the United States has been carrying out drone attacks in several countries, including Yemen, Pakistan, Afghanistan and Somalia. The aerial attacks were initiated by former US President George W. Bush but have been escalated under President Barack Obama.

Former US drone operator Brandon Bryant, who was involved in the killing of more than 1600 people, revealed earlier this year that aerial strikes are conducted with complete uncertainty. Bryant, who worked for almost five years in America's secret drone program bombing targets in Afghanistan and other countries, such as Pakistan and Iraq, said operators lacked visibility and were not sure about the identity of the people they were shooting at. Bryant said: "We see silhouette, shadows of people, and we kill those shadows."