Weapons sold by 17 countries - including Britain, Russia and the United States - are being used by militias to commit war crimes in Iraq, according to Amnesty International.
The Amnesty report focuses on Popular Mobilisation Units, which are a crucial part of the Iraqi government's strategy in fighting ISIL.
The Shia militias were officially made part of Iraq's security forces two months ago.
The rights group is also detailing human rights abuses by the militias in Iraq.
Who's to blame?
And how safe is it for civilians fleeing the city of Mosul?