The Syrians were being held behind barbed wire fences around the Turkish crossing of Akcakale in the southeast of the country.

They are fleeing a looming battle as Kurdish forces advance on the Syrian town of Tal Abyad, which is held by Islamic State of Iraq and Syria (ISIS) (ISIS) militants and lies just across the Turkish border.

The Britain-based Syrian Observatory for Human Rights said earlier that Kurdish People’s Protection Units (YPG) had advanced to within 10 kilometers of Tal Abyad.

The Turkish forces used water cannon and fired warning shots into the air to keep the Syrians away from the border fences, the correspondent said.

With more Syrians still arriving from Tal Abyad, tensions remained high with Turkish police and soldiers deployed right on the border fence to ensure no one slipped through.

Most of the women arriving from the ISIS-controlled town were clad in black with full face veils. Many carried white sacks of possessions on their head.

Turkish forces were not allowing any Syrians through the border gate.

Despite the Kurdish advance, the black flag of ISIS could however still be seen flying over the town of Tal Abyad, the correspondent added.

Turkey had said on Thursday it was taking measures to limit the flow of Syrian refugees after an influx of thousands more over the last days due to the fighting between Kurds and militants.

Under an “open-door” policy championed by President Recep Tayyip Erdogan, Turkey has taken in 1.8 million Syrian refugees since the conflict in Syria erupted in 2011.

But Deputy Prime Minister Numan Kurtulmus said at Akcakale crossing on Thursday that new entries would only be considered in case of a humanitarian tragedy.

The government has emphasized that this does not mean any end to the “open door” policy. But it is not clear if the Syrians caught in the current situation will be allowed through.

Officials have said that Turkey had taken in over 13,500 refugees over the last days escaping the fighting for Tal Abyad.

The Turkish government has over the last months expressed increasing bitterness that it has been left to shoulder the burden of refugees while the West stands by.

The government said in April it has spent almost $5.5 billion (4.8 billion euros) to provide for Syrian refugees since the crisis began in 2011.