The secret report, obtained and published this week by the Bureau for Investigative Journalism, claims at least 147 of 746 people killed in 75 drone strikes in Pakistan between 2006 and 2009 "are clearly stated to be civilian victims" and "94 of those are said to be children."
U.S. officials, speaking on condition of anonymity, told ABC News the findings are unsubstantiated, with questionable methodology and what one official called "far from authoritative."
The notion that the United States has undertaken operations in Pakistan that resulted in the deaths of hundreds of innocent Pakistanis is ludicrous," the official said. "There is no credible information whatsoever to substantiate the report's distorted figures," the official said.
The United States had previously acknowledged the accidental deaths of civilians in its drone program, but put the number since 2004 at closer to 50, ABC News said.