Islamic State has seized new territory from Syrian rebels in northern Syria, advancing in an area where Turkey and the United States are planning to open a new front against the group.
The Syrian Observatory for Human Rights, a UK-based group tracking the war, said it had seized five villages including two near the Turkish border from other Syrian insurgents.
Islamic State announced it had captured three villages in the area and said its fighters had nearly encircled the rebel-held town of Marea, some 20 km (12 miles), south of the Turkish border.
Turkish Foreign Minister Mevlut Cavusoglu told Reuters on Monday that the two NATO allies would soon launch "comprehensive" air operations to flush Islamic State fighters from the border region.
The villages captured by Islamic State include two that the al Qaeda-linked Nusra Front recently handed over to another Syrian rebel group.
Islamic State has escalated attacks against Syrian rebels in the northern Aleppo countryside since Turkey announced plans to drive the group from the area.
The Nusra Front, which is hostile to Islamic State, announced earlier this month that it would withdraw from the area where Turkey plans to establish a buffer zone.