U.S.-Backed Forces Begin Assault on Raqqa, ISIS Stronghold in Syriabr Residents of Raqqa say that in recent weeks numerous Islamic State fightersbr and their families have left the city, heading southeast along the Euphrates to the city of Mayadeen, in Deir al-Zour Province.br By ANNE BARNARDJUNE 6, 2017br BEIRUT, Lebanon — Forces backed by the United States said on Tuesdaybr that they had begun a long-anticipated offensive against Islamic State militants in the northern Syrian city of Raqqa, the group’s self-proclaimed capital.br The forces, collectively called the Syrian Democratic Forcesbr and made up of Syrian Kurdish fighters and Arab militias, have over the past month surrounded Raqqa from the east, north and west.br American and British forces there are training Syrian opposition fighters to battle the Islamic State,br and airstrikes were carried out under similar circumstances on May 18, officials said.br Pentagon officials insisted that the surge in tensions between the Saudibr and Qatari camps — both members of the anti-Islamic State coalition — would not affect operations against the militant group in Raqqa and Mosul, Iraq.