"While rebels were entering the Turkman Barih village on Sunday, landmines planted by the ISIS terrorists exploded, Killed 6, also wounding 29 other rebel militias," the Britain-based Syrian Observatory for Human Rights said.
However, local Turkish media quoted an army statement as saying "clashes in northern Syria have killed 15 Ankara-backed Free Syrian Army (FSA) fighters in the last 24 hours."
This is the largest death toll inflicted among the ranks of the rebels since they started their offensive backed by the Turkish army and planes against Islamic State near the Turkish-Syrian border on August 24.
The incident prompted the rebels to withdraw from the area they had managed to take control of on Sunday, located 13 kilometres south-west of the strategic border town of al-Rai.
Al Rai is one of the centres of Turkey's recent ground intervention in support of Syrian rebels against Islamic State and Kurdish-led forces.
The ISIS used the area north-east of Aleppo, to bring foreign fighters into its territories in Iraq and Syria.
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