Fighters from the Kurdish People's Protection Units (YPG) took up positions on the Syrian part of the Akcakale-Tal Abyad border post, which lies on IS's main supply route to its de facto capital of Raqa, the photographer said.

The Kurdish fighters had advanced on Tal Abyad in a two-pronged offensive from east and west.

For the second consecutive day, Turkish authorities allowed at least 3,000 Syrians who were fleeing the fighting to cross into Turkey through the Akcakale post.

An estimated 20,000 Syrians have crossed the Turkish border since last week, despite sporadic border closures.