AKÇAKALE, Turkey (AFP) - Turkey on Sunday began accepting onto its territory Syrian refugees fleeing the battle between Kurds and ISIS extremists for the Syrian border town of Tal Abyad, an AFP photographer said.

Dozens of Syrian refugees, many carrying sacks of possessions, started passing through the Akcakale border gate onto Turkish territory as thousands more awaited their turn to cross on other side.

Turkey had for several days been blocking the Syrians from entering Turkey, saying it would only allow them into the country in the event of a humanitarian tragedy.

However, local officials in Akcakale said earlier that permission had been received from Ankara to allow the refugees to cross into Turkey.

The decision came as Kurdish forces advanced on Tal Abyad, which is controlled by ISIS (Islamic State in Iraq and Syria) militants who have captured swathes of Syria and Iraq.

A delay followed which Turkish television said was due to the ISIS extremists impeding the refugees from crossing on the other side of the border.

Amid chaotic scenes, some Syrians managed to push their way through the border fences away from the actual Akcakale border gate to cross illegally into Turkey.

Some squeezed under the mesh-wire fences while others managed to climb over, with bags thrown the fence. Many carried young children.

The army immediately used water cannon and tear gas in a bid to restore control.

But in the early evening the Turkish authorities opened the Akcakale border gate and the refugees began to enter in an orderly fashion.

Many had relatives already waiting for them on the other side. The queue of refugees could be seen extending up the hillside.

With temperatures above 35 degrees Celsius, Turkish emergency workers threw bottled water into the crowds as dozens of hands stretched out to catch them.

The refugees were then registered with the Turkish authorities. Those with relations already in Turkey can stay with them, others will be taken to existing refugee camps, the Dogan news agency said.

Turkish television said that in all 3,000 people were expected to cross over into Turkey.

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.

The Turkish government has over recent 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 US$5.5 billion (S$7.4 billion) to provide for Syrian refugees.

Before the closure of the border last week, Turkey had taken in more than 13,500 Syrian refugees escaping the fighting for Tal Abyad, officials said.

Turkish officials have said that the refugees are mainly ethnic Arabs and Turkmen.

Erdogan earlier said he was troubled by the advance of Kurdish forces to Tal Abyad, saying they could in the future threaten Turkey.

He said the places refugees had vacated were being occupied by the Syrian Kurdish group the Democratic Union Party (PYD) and the outlawed Kurdistan Workers Party (PKK).

"This is not a good sign," he said. "This could lead to the creation of a structure that threatens our borders."