Kurds say the rebels had pledged to stay out of their districts. Kurdish groups have for the most part tried to steer a middle course in the conflict between the rebels and the regime of President Bashar al-Assad. Some figures have allied with the rebels, others with Assad, while others have remained neutral.

The UK-based Syrian Observatory for Human Rights said 19 rebels and three Kurdish gunmen were killed in the clash that lasted several hours, the group said.