An Arab-Kurdish alliance backed by US-led coalition air strikes advanced Tuesday in the jihadist stronghold of Manbij in northern Syria, where it now controls 60 percent of the town, a monitor said.
Syrian Democratic Forces have been fighting to seize the key town near the border with Turkey from the Islamic State group since late May.
With the support of coalition air raids, SDF forces advanced Tuesday into the east and west of the town, while IS forces retreated to the north and centre of Manjib, said the Syrian Observatory for Human Rights.
That allowed the SDF to open a route between Manjib and Hassaka, a Kurdish stronghold around 150 kilometres (90 miles) to the east, said the Britain-based monitoring group.
Manbij sits on the route between the Turkish border and the eastern city of Raqa, the jihadists' de facto capital in Syria.
The fate of thousands of civilians inside Manbij has raised fears among humanitarian agencies.
Syria's conflict has killed more than 280,000 people and drawn in world powers on both sides since it erupted in March 2011.