Tens of thousands of Syrian Kurds have crossed into Turkey over the past day, fleeing an advance by Islamic State fighters who have seized dozens of villages close to the border, Turkish Deputy Prime Minister Numan Kurtulmus said on Saturday, Sept 20, according to Reuters.

Turkey opened a stretch of the frontier on Friday, after Kurdish civilians fled their homes, fearing an imminent attack on the border town of Ayn al-Arab, known as Kobani in Kurdish.

"Around 45,000 Syrian Kurds have crossed the border as of now from eight entrance points along a 30-km distance from Akcakale to Mursitpinar since we opened the border yesterday," Kurtulmus told CNN Turk television.

Islamic State's advances in northern Syria have prompted calls for help by the region's Kurds who fear an impending massacre in the town of Kobani, which sits in a strategic position close to the Turkish border.

At least 18 Islamic State fighters were killed in clashes with Syrian Kurds overnight as the militant group took control of more villages around the town, according to the Syrian Observatory for Human Rights, which monitors the war.

Iraqi Kurdish leader Masoud Barzani called on Friday for international intervention to protect Kobani from the Islamic State advance, saying the insurgents must be "hit and destroyed wherever they are".

The United States is drawing up plans for military action in Syria against the radical Sunni Muslim group which has seized swathes of territory in Syria and Iraq, proclaiming a caliphate in the heart of the Middle East.