Ankara says tens of thousands of Syrian Kurds have crossed into Turkey over the past day, fleeing clashes with Islamic State militants.
Turkish Deputy Prime Minister Numan Kurtulmus told reporters on September 20 that "around 45,000 Syrian Kurds have crossed the border from eight entrance points" since Turkey opened the frontier on September 19.
The exodus was prompted by intense clashes between Islamic State forces and Kurdish fighters trying to hold off an assault on the town of Ain al-Arab, known as Kobane by the Kurds.
It is the third-largest Kurdish town in Syria and a strategic location, because it lies on the border with Turkey in the northern Aleppo province.
Islamic State militants in recent days have seized at least 60 villages around the town.
The group's latest advance prompted the Iraqi Kurdish leader, Masud Barzani, to urge the international community to save Syria's Kurds from the militants' onslaught.
Turkish Prime Minister Ahmet Davutoglu said on September 19 that Ankara's priority is to help those in need on the Syrian side of the border, but "if that's not possible then of course they will be given help" inside Turkey."
On September 20, the Syrian Observatory for Human Rights, a Britain-based monitor, said 300 Kurdish fighters had entered Syria from Turkey to reinforce the Syrian Kurdish People's Protection Units (YPG) fighting Islamic State.
The group said 18 IS fighters were killed in clashes overnight.
The United States has organized a coalition of countries to tackle IS jihadists, who have declared an Islamic "caliphate" in parts of Syria and Iraq and carried out abuses including beheadings and crucifixions.
U.S. President Barack Obama plans to make his case against Islamic State before the world at the UN General Assembly next week in a bid for more international support.