Raqqa will be part of a decentralised federal Syria now the city has been freed from Islamic State, the US-backed militias that captured it said on Friday, tying its political future to Kurdish-led autonomy plans for northern Syria.
The Syrian Democratic Forces said the handover would not be immediate, with SDF fighters still combing the city of Raqqa.
The group kicked off its first working session in a seafront hotel on the island of Ischia on how to deal with the potential return to Europe of foreign fighters fleeing a crumbling Islamic State group.
Thirteen rebels among the few dozen Islamic State loyalists holed up in the decimated heart of Marawi City were killed in the operation and Malaysian Mahmud Ahmad was likely among them.
Days ago in Syria's Raqqa, die-hard jihadists made their final stand in the city's national hospital. On Wednesday, it stood eerily silent, its entrance inhabited only by swarming flies and two rotting corpses.
US-backed forces took full control of Raqqa from the Islamic State group on Tuesday, defeating the last jihadist holdouts in the de facto Syrian capital of their now-shattered "caliphate".
In the second day of a lightning government campaign to take back towns and countryside from forces of the Kurdish autonomous region, Kurdish troops known as Peshmerga pulled out of the long disputed Khanaqin area.
Duterte led rain-soaked soldiers in celebrations in Marawi, a day after the military announced the death of the head of the Islamic State group in Southeast Asia, Isnilon Hapilon, in a gunbattle in the city
Raqqa was once the de facto Syrian capital of the jihadists' self-styled "caliphate" in Syria and Iraq, but IS now holds just 10% of the city.
The army previously set a target of Sunday to end the fighting in Marawi, which it said has killed more than 1,000 people.