The northern Syrian city of Kobane, or Ayn al Arab, is under heavy siege by Islamic State militants for the third consecutive day. The Islamic State is reported to have taken control of 21 villages outside of Kobane.

Since 2012, Kobane has been controlled by the People’s Protection Units (YPG), a Kurdish force affiliated with the Turkish Kurdistan Workers Party (PKK), a US-designated Foreign Terrorist Organization. The YPG have since considered Kobane to be part of Rojava, or Syrian Kurdistan.

The Islamic State first tried to seize Kobane in July, but was fended off by the YPG, with the likely help of the PKK. Since then, there has been sporadic fighting between Kurdish forces and the Islamic State in the surrounding villages. […]