==REUTERS CANNOT INDEPENDENTLY VERIFY THE CONTENTS OF THIS VIDEO==<br/> <br />Amateur video uploaded to a social website, appears to show Syrian Kurdish fighters engaged in a fierce battle with Islamic State (IS) in northern Syria on Wednesday (September 17).<br/> <br />The video shows members of the main Kurdish group in Syria, the YPG, clashing with IS near the Kurdish city of Ayn al-Arab, also known as Kobani.<br/> <br />A tank belonging to IS appeared to retreat after coming under YPG fire.<br/> <br />The Syrian Observatory for Human Rights says that, in an advance near the border with Turkey, IS fighters using heavy weaponry including tanks, seized a group of Kurdish villages near Kobani.<br/> <br />The group says Kobani itself was besieged, with 21 villages falling to IS fighters advancing on the city.<br/> <br />A YPG spokesman said Islamic State had encircled Kobani and was using tanks, rockets and artillery in the attack.<br/> <br />Islamic State has been trying to establish control over a belt of territory ne
