New evidence collected by Human Rights Watch shows that the mass executions ISIS committed in June were on a larger scale than anyone imagined. Previously, ISIS bragged that it executed 1,700 soldiers near Tikrit around June 14. Only about 160 of those deaths were confirmed by HRW then, but now the group says 560 to 770 Iraqis were mass killed.

Per the Associated Press:

The Human Rights Watch ... said the revised figure for the slain soldiers was based on analysis of new satellite imagery, militant videos and a survivor's account that confirmed the existence of three more "mass execution sites." The number of victims may well be even higher as more evidence emerges ...

HRW adviser Fred Abraham said today, "These are horrific and massive abuses, atrocities by the Islamic State, and on a scale that clearly rises to the crimes against humanity."

Back in June, ISIS posted grim images of the executions online.

Outgoing Prime Minister Nouri al-Maliki said today that Iraqi troops killed some members of ISIS who carried out this attack and that "security forces were pursuing" more.

[Image via AP]