The rebels, whom Turkey has supported with tanks and air strikes, had been pushing towards the IS stronghold of Dabiq, a village with symbolic importance to the jihadists.
The IS attack, which began late on Friday, retook villages including Akhtarin and pushed towards Turkman Bareh, some 3 km east of Dabiq, said the British-based Observatory, which tracks the war using contacts on the ground.
Satellite dishes damaged by Islamic State militants are pictured inside a mosque in Turkman Bareh village, after rebel fighters advanced in the area, in northern Aleppo Governorate, Syria
Islamic State militants captured several villages from Syrian rebels in a counter-attack near the Turkish border that forced the foreign-backed insurgents to retreat, the Syrian Observatory for Human Rights reported.