BEIRUT (AP) — Islamic militants using weapons they recently seized in neighboring Iraq intensified an offensive against Kurdish areas in northern Syria as they fight to expand the territory under their control, activists said Thursday.

The clashes came as a Syrian watchdog group said the death toll in Syria’s three-year conflict has climbed to 171,000, reflecting the relentless bloodletting in a civil war that appears no closer to being resolved. Nearly half of the dead were civilians, the Syrian Observatory for Human Rights said.