Reuters: Kurdish forces backed by Syrian insurgent groups took control of a hill inside the provincial stronghold of the militant Islamic State group on Sunday after deadly clashes, the Syrian Observatory for Human Rights said.

The Kurdish forces, supported by U.S.-led air strikes, drove Islamic State fighters from the town of Kobani last month near the Turkish border and have pushed them back from surrounding villages in northern Syria. Islamic State still holds tracts of land across northern and eastern Syria and into Iraq.

Now the Kurds and other local fighters who oppose Islamic State have taken a hill south of Kobani which lies within Raqqa province – the stronghold of the al Qaeda offshoot in Syria, said the Observatory, which tracks the conflict through sources on the ground.

“It is the first time they get into Raqqa,” the Observatory’s founder Rami Abdulrahman said. He added that at least 35 Islamic State fighters and four members of the Kurdish forces had been killed on Sunday in battles near Kobani, which were the heaviest since the Kurds took back the town.