Islamic State fighters besieged a Kurdish city in northern Syria on Thursday after seizing 21 villages in a major assault, prompting a call to arms from Kurds in neighboring Turkey who urged followers to go and help resist the group's advance.
The attack on the city of Ayn al-Arab, known as Kobani in Kurdish, came two days after the top U.S. military officer said the Syrian opposition would probably need the help of the Syrian Kurds to defeat Islamic State.
With the United States planning to expand military action against Islamic State from Iraq to Syria, a surveillance drone was spotted over nearby Islamic State-controlled territory in Aleppo province, the Syrian Observatory for Human Rights, which tracks Syria's civil war, said.