Tens of thousands of Syrian Kurds have flooded into Turkey, fleeing an onslaught by the jihadist Islamic State group that prompted an appeal for international intervention.
Turkish Deputy Prime Minister Numan Kurtulmus said more than 60,000 Syrian Kurds had crossed into the country since the frontier was opened on Friday.
The exodus was prompted by intense clashes between IS and Kurdish fighters trying to hold off an assault on the town of Ain al-Arab, known as Kobane by the Kurds.
Since Tuesday night, IS fighters have been advancing on the town, hoping to seize it and secure their control over a large swathe of Syria's northern border with Turkey.
The group has quickly seized at least 63 surrounding villages, although the Syrian Observatory for Human Rights, a Britain-based monitor, said 18 IS fighters were killed in clashes overnight.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
It said 13 jihadists were killed on Saturday, and that 25 Kurdish fighters have been killed since Tuesday.
On Saturday, the Observatory said 300 Kurdish fighters had entered Syria from Turkey to reinforce the Syrian Kurdish People's Protection Units (YPG) fighting IS.
"The IS came to our village and threatened everyone. They bombed our village and destroyed all the houses. They beheaded those who chose to stay," said Mohammed Isa, 43, who left with his family of seven.
IS's advances have prompted calls from Syria's opposition and Kurdish officials for international intervention, with one leader warning of "ethnic cleansing".
The United States has organised 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.
The Syrian opposition National Coalition urged international air strikes to "stop mass atrocities" if IS advances into Ain al-Arab.
"Air strikes are needed to help opposition forces protect vulnerable civilians," the coalition's US representative Najib Ghadbian said.
And Salih Muslim Mohamed, a leader of the Democratic Union Party (PYD), urged the United States and Europe to help Ain al-Arab avoid the fate of the Iraqi town of Sinjar, which has been emptied of its Yazidi minority residents in the wake of an IS onslaught.
"Kobane is facing the most barbaric attack in its history," he warned.
"If you want to avoid an ethnic cleansing even more barbaric than that in Sinjar, you must support Kobane because the next few hours will be decisive," he added in a statement late Friday.
Obama said last week he was ready to launch strikes on IS fighters in Syria, expanding the campaign already underway in Iraq, but so far there have been none.
The Observatory reported on Saturday that IS militants had executed at least 11 Kurds, and that the fate of some 800 residents who fled their villages remained "unknown".
