The defeat of ISIS in its Syrian bastion of Raqaa was a "historic" achievement, the US-backed Syrian Democratic Forces that led the months-long battle said Friday, adding the city would be part of decentralized Syria. "We dedicate this historic victory to all humanity," said Talal Sello, spokesman for the Kurdish-led SDF, at an official ceremony in the city. "We in the general command of the Syrian Democratic Forces announce that we will hand over the administration of the city of Raqqa and the surrounding countryside to the internal security forces in Raqqa," Sello added, referring to part of a civil authority set up for the city. But Sello said the handover would not be immediate, with SDF fighters - who took full control of Raqqa on Tuesday -still combing the city, which lies in ruins and littered with explosives. "After the end of clearing operations... we will hand over the city to the Raqqa Civil Council," he said. The RCC was created some six months ago, and is made up of local officials and tribal leaders who will face the daunting task of rebuilding the city. "We pledge to protect the borders of the province against all external threats, and we confirm that the future of Raqqa province will be determined by its people within the framework of a decentraliized, federal democratic Syria in which the people of the province will run their own affairs," the SDF said, according to Reuters. In a highly symbolic move, the press conference was held inside Raqqa’s sports stadium which ISIS militants had turned into an arms depot and a huge prison where they incarcerated and tortured their opponents. Standing before a backdrop of shattered buildings, Sello urged the international community and aid organizations to assist with the citys reconstruction. Raqqa become the de facto Syrian capital of ISIS’ self-styled "caliphate" in Syria and Iraq after the terrorist group captured it in 2014. The SDF, a Kurdish-Arab alliance backed by the US-led coalition, broke into the city in June after months of fighting to surround it. The Britain-based Syrian Observatory for Human Rights monitor estimates over 3,000 people, at least a third of them civilians, were killed in the fighting. Associated Press drone footage from Raqqa showed the extent of devastation caused by weeks of fighting and thousands of bombs dropped by the US-led coalition. Footage from Thursday shows the bombed-out shells of buildings and heaps of concrete slabs lay piled on streets littered with destroyed cars. Entire neighborhoods are seen turned to rubble, with little sign of civilian life. The video showed entire blocks in the city as uninhabitable with knocked-out walls and blown-out windows and doors, while some buildings had several stories turned to piles of debris. The stadium appears to have suffered less damage compared with surrounding buildings.