Islamic State seized a hilly area southeast of the Syrian city of Aleppo, it and monitors said on Friday, after making advances near the border with Turkey that the United Nations said forced inhabitants to flee.
The militant jihadist group said in a statement it had gained control over Dureihem and surrounding hills about 65 km (40 miles) southeast of Aleppo, an area that overlooks the government-held town of Khanaser.
Syrian state media reported late on Thursday that the army had engaged in operations against Islamic State near Khanaser, inflicting "large losses" on the insurgents.
Fighting between the army and Islamic State in the area continued as the government sought to regain control there, the Syrian Observatory for Human Rights, a Britain-based group that tracks Syria's civil war, said on Friday.
The United Nations said that as of Thursday, an Islamic State attack on border areas held by Syrian rebel groups had put camps for displaced people at risk, causing more than 20,000 of them of them to flee towards the opposition-held town of Azaz.
On Monday, Islamic State retook the town of al-Rai, 36 km (22 miles) east of Azaz, from factions fighting under the banner of the Free Syrian Army, part of months of back-and-forth fighting in northern Aleppo province.
The Syrian army backed by Russian warplanes launched an assault north of Aleppo on Thursday, threatening to block a vital rebel route into the city in fighting that has cast new clouds over peace talks in Geneva.