Islamic State (IS) fighters have seized a string of Kurdish villages in northern Syria.
The London-based Syrian Observatory for Human Rights said on September 18 that 16 villages were seized in the previous 24 hours around the town of Ayn al-Arab at the border with Turkey.
It said Kurdish fighters defending the town were being encircled in a "pincer movement" by IS militants using artillery and tanks.
The deputy commander of Kurdish forces in Ayn al-Arab, Ocalan Iso, told Reuters that the Kurds were seeking support from other groups, including the armed Kurdish Workers' Party to fend off the advance.
West of Ayn al-Arab, Syrian activists told AP that government helicopter gunships attacked on September 18 the town of Al-Bab held by IS militants, killing at least 12 people and wounding dozens.