Fighters from the US-backed Syrian Democratic Forces have captured most of Raqqa from ISIS, saying the campaign to put the Syrian city under SDF control was in its final stages. The Syrian Observatory for Human Rights said the SDF overran five strategic neighborhoods in Raqqa. "Because of the heavy (US-led) coalition air strikes, ISIS withdrew from at least five key neighborhoods over the past 48 hours," said Observatory chief Rami Abdel Rahman. "This allowed the Syrian Democratic Forces to control 90 percent of the city."  The terrorist organization has pulled out of the north of the city and abandoned its grain silos and mills. But the SDF said its fighters had seized only 80 percent of Raqqa city. In a statement, the SDF said it had opened a new front against ISIS on the northern edge of Raqqa, describing this as "a feature of the final stages of the Euphrates Wrath campaign, which is nearing its end". "ISIS is now confined to the city center," Abdel Rahman said. "The difficulty in advancing and fully clearing these neighborhoods is linked to the mines that ISIS has left behind." The extremist group seized Raqqa in early 2014, transforming the city into the de facto Syrian capital of its self-declared “caliphate.” It quickly became synonymous with the terrorist organizations most gruesome atrocities, including public beheadings. Backed by US-led coalition air strikes, the SDF, an alliance of Kurdish and Arab militias, spent months encircling the city before entering it in early June.   Tens of thousands of civilians have fled the fighting in recent months. Estimates of the number still inside the city range from fewer than 10,000 to as many as 25,000.