The brutal Sunni militant group Islamic State of Iraq and the Levant (ISIS) has released a gruesome set of photos that reportedly depicts the mass execution of Shi'ite Iraqi soldiers.

Released on the group's Twitter account — where they boasted of killing 1,700 soldiers — fighters show off the trucks and gear they had seized in their takeover of Mosul and Tikrit. But others are much worse, with dozens of people bound and packed into the back of trucks and shuttled to a mass grave in the desert.

Numerous photos appear to show masked ISIS fighters killing the bound men as they lie helpless on the ground. Needless to say, they are extremely disturbing, and if confirmed, are evidence of a major war crime.

While they appear to be genuine, the photos nor the claim of 1,700 deaths has been verified by human rights groups, according to the Sydney Morning Herald.

Aaron Zelin, a researcher at the Washington Institute for Near East Policy and expert on militant Islam, explained how these types of executions are meant to incite all-out civil war:

Point of ISIS mass executions is to radicalize Shi’a population, so Shi'a do the same to Sunnis, so ISIS then becomes protectors of Sunnis. — Aaron Y. Zelin (@azelin) June 14, 2014

"There will be particular scrutiny of the conduct of ISIS, given their well-documented record of committing grave international crimes in Syria," Navi Pillay, United Nations High Commissioner for Human Rights, told the Herald.

The situation in Iraq has become increasingly worse in recent days, as militants — having already taken control of Fallujah — seized the key cities of Tikrit and Mosul. With Mosul in the north ISIS scored its biggest victory, taking control of the country's second-largest city, home to roughly 2 million people.

ISIS, once an affiliate of Al Qaeda, was actually expelled from that organization for being too extreme, The Washington Post reported.

We have chosen not to show many of the worst photos here, and have heavily-blurred images of the victims. However, if you wish to see the full set, they are here (WARNING: EXTREMELY GRAPHIC AND DISTURBING).

The end of this page has very upsetting photos of ISIS murdering kneeling people en masse. This is pure evil. http://t.co/tNBX8MCa6O — joshuafoust (@joshuafoust) June 14, 2014



