Human rights advocacy organization Reprieve has compiled a report that challenges the accuracy of the US drone program seeking to assassinate targets named on the United States’ controversial “kill list”.

According to the report, at least 1,147 unknown civilians have been killed by US drone strikes while pursuing 41 terrorists in Pakistan and Yemen between November 2002 and November 2014. The report also claims that those 41 terrorists were inaccurately reported to have been killed more than once, sometimes multiple times.

“In total, as many as 1,147 people may have been killed during attempts to kill 41 men, accounting for a quarter of all possible drone strike casualties in Pakistan and Yemen. In Yemen, strikes against just 17 targets accounted for almost half of all confirmed civilian casualties,” the report states. “Yet evidence suggests that at least four of these 17 men are still alive. Similarly, in Pakistan, 221 people, including 103 children, have been killed in attempts to kill four men, three of whom are still alive and a fourth of whom died from natural causes.”

“Drone strikes have been sold to the American public on the claim that they’re ‘precise’. But they are only as precise as the intelligence that feeds them,” Jennifer Gibson, the Staff Attorney at Reprieve who organized the report, told The Guardian. “There is nothing precise about intelligence that results in the deaths of 28 unknown people, including women and children, for every ‘bad guy’ the US goes after.”

Reprieve collected data from media reports and leaked information from officials in the United States, Pakistan and Yemen to organize the report, and pointed out significant discoveries in its compilation:

• 24 men in Pakistan were reported as killed or targeted multiple times. 874 people, including 142 children, were killed as a result of the strikes.
• 17 men in Yemen were reported killed or targeted multiple times. 273 people were killed as a result of the strikes.
• While targeting al Qaeda leader Ayman al-Zawahiri 105 people were killed, including 76 children. Two attempts to target Ayman al-Zawahiri  have failed and he is reportedly still alive.
• It took six attempts to kill targeted terrorist suspect Qari Hussain, and 128 people died during those attempts.
• Every assassination target was reported to have been killed more than three times on average before being accurately reported as dead.

“These ‘high value targets’ appear to be doing the impossible – dying not once, not twice, but as many as six times. At the same time, hundreds of unknown men, women and children are also caught in the crosshairs,” said Gibson in a press release.”President Obama continues to insist drone strikes are ‘precise’, but when targeting one person instead kills as many as 128 others, there’s only one conclusion that can be drawn – there’s nothing targeted about the US drone programme.”

Reprieve’s full report is available to read here.