The United States wants countries to repatriate the fighters, while the Kurds want to set up an international tribunal. All the allies want the extremists behind bars.
The fall of Baghouz, the last remaining bastion of ISIS, marks the death of its so-called 'caliphate', but the threat of the terrorist group remains.
Recent gains brought a months-old operation to wipe out the last vestige of ISIS's once-sprawling proto-state closer to its inevitable outcome.
His location is unknown, but many speculate he is near the Afghan-Pakistani border.
'It is time to put an end to this human misery and tragedy,' said Tadamichi Yamamoto, head of the UN mission in Afghanistan.
Afghan officials suggested the latest bombing appeared to be an attempt to derail the burgeoning peace process, vowing that it would not go unanswered.
Although ISIS claimed responsibility, President Ashraf Ghani put part of the blame on the Taliban and on sanctuaries of suicide bombers in neighbouring countries.
A suicide bomb tore through a banquet hall filled with hundreds of religious scholars gathered to mark the Prophet Mohammad's birthday, killing at least 55 people.
Thousands of people abandoned their homes in Hazara-dominated areas in the province the past week, as the Taliban intensified their fighting, killing dozens of innocent civilians.
Through threats of violence and imprisonment, the Taliban militants pressure local farmers to pay ushr and then use the proceeds to fight the Afghan government, locals say.