Though the Pentagon has mostly issued blanket denials whenever they're caught killing civilians in airstrikes against ISIS targets anyhow, officials say their eagerness to escalate the air war against ISIS targets has seen the implementation of new rules allow the US to kill larger numbers of civilians per attack.

The details are still scant, with the official rules likely to remain a secret, but officials say they have implemented a "sliding scale," based on the region being targeted and the "opportunity." In some cases, US airstrikes will be allowed to kill 10 civilians per strike.

This was seen previously in incidents where US forces attacked sites believed to contain physical cash. In both cases, the attacks took place in residential neighborhoods, and the Pentagon insisted they were "comfortable" with the number of civilians killed.

Despite officials being pretty open about killing civilians in those cases, the deaths were never included in the official Pentagon figures for civilians killed. Overall, the Pentagon is believed to have killed several hundred civilians in the ISIS air war since 2013, though the official admissions are to only 14 deaths.