The Security Council is putting the final touches on a resolution that would authorize U.N. investigators to help Iraq collect evidence to prosecute extremists from the Islamic State group for possible war crimes.

A council diplomat, speaking on condition of anonymity because negotiations are private, said Saturday the council hopes to vote next Thursday.

The draft resolution would ask Secretary-General Antonio Guterres to establish an investigative team to assist Iraq in preserving evidence "that may amount to war crimes, crimes against humanity and genocide" committed by IS.

Iraqi Foreign Minister Ibrahim al-Jaafari wrote to Guterres last month saying it was working on a draft resolution with Britain. Human rights lawyer Amal Clooney had urged Iraq's prime minister in March to send a letter seeking U.N. assistance.