The battle to flush Islamic State (IS, formerly ISIS/ISIL) out of its last holdouts in Raqqa, Syria could drag on for “weeks,” French Defense Minister Florence Parly said on Friday. “It’s probably a question of weeks,” she told France Inter radio. “It’s a slow, difficult battle but which is nonetheless effective,” the minister added. The US-backed Syrian Democratic Forces, an alliance of Kurdish and Arab fighters, has wrested 90 percent of the city from the extremists since June. France is part of the US-led coalition carrying out airstrikes on IS positions in Iraq and Syria, where around 500 French extremists remained, according to Parly.