US-backed Militias Launch Final Assault on IS Stronghold in RaqqaU.S.-backed militias said Sunday they have launched their final assault on Raqqa, the northern Syria city Islamic State has claimed as the self-declared capital of its religious caliphate. The Kurdish-led Syrian Defense Forces (SDF) said that about 275 Syrian Islamic State fighters and their families were allowed to leave the city held by the jihadists since a 2014 takeover, leaving "no more than" 200 to 300 militants to fight on. Raqqa's fall could be imminent, with the SDF saying the operation would continue "until all the city is cleansed from terrorists who refused to surrender." But Colonel Ryan Dillon, a spokesman for the U.S.-led international coalition supporting the Kurdish and Arab militias fighting to seize Raqqa, said, "We still expect there to be difficult fighting." Islamic State took over Raqqa as it claimed vast swaths of Iraq and Syria three years ago before steadily losing back territory in the last two years. The SDF decided to hasten the end of fighting in Raqqa by allowing the 275 Islamic State fighters and their families to leave, but the jihadists did not release them as originally agreed, instead taking them further away to another stronghold. The SDF described the civilians as human shields for the fighters. Dillon said the U.S.-led coalition did not agree with the SDF's evacuation plan, "but we have to respect their solutions." Fighting over Raqqa has raged since June 6, a city where Islamic State at times had celebrated its battlefield victories with parades. The jihadists imprisoned its captives there, executed dozens of captured Syrian soldiers and created a slave market for Yazidi women captured in Iraq and given to fighters. The U.S.-led coalition said Raqqa was the hub for international terrorist attacks abroad, including the November 2015 attack that killed 130 people in Paris. In more recent times, Islamic State not only faced the SDF offensive, but also attacks from the Syrian army supported by Russia, Iran and allied Shiite militias. Activists say more than 1,000 civilians have been killed in Raqqa since the battle to retake the city began. Nearly 270,000 people have fled since April. Before the departure of the group of 275, an SDF spokesman said that any Islamic State fighters left behind would be forced to "surrender or die." On Friday, scores of civilians fled Raqqa ahead of the anticipated final push into the city by the U.S.-backed fighters. Residents said local IS fighters had been surrendering recently, but the militants still held on to a few areas of the city, including the stadium and national hospital.\n\nMany of the residents who escaped the city were malnourished after being trapped by the fighting for several months.\n\n"Those who manage to escape speak of deteriorating conditions inside the city," U.N. refugee spokesman Andrej Mahecic said. "Food, water, medicine and electricity are scarce."