U.S.-backed forces are close to liberating the eastern Syrian city of Raqqa from the Islamic State militant group (ISIS) after a mass withdrawal, meaning it is “game over” for the jihadi capital of the self-styled caliphate, a Syrian monitoring group told Newsweek on Wednesday.

Rami Abdelrahman, director of the Syrian Observatory for Human Rights (SOHR), a U.K.-based monitoring group that has an extensive network of rebel and activist sources in Syria, said that the Kurdish-Arab coalition known as the Syrian Democratic Forces, or SDF, now controls “over 90 percent” of the city’s neighborhoods.

He said that just a small number of ISIS militants remain in the city center, where they are encircled, after many of the group’s ranks inside the city withdrew from five neighborhoods while under siege from the U.S.-led coalition’s airstrikes.