Islamic State fighters have entered the northern Syrian city of Kobane, battling Kurdish forces, activists say, the BBC reports.
The Syrian Observatory for Human Rights says a number of people were killed in fierce clashes in the centre of the town on the Syrian-Turkish border.
Kurdish forces drove IS forces from Kobane early this year after a long campaign backed by US-led air strikes.
The battle made international headlines – heralding what some saw as a symbolic defeat for the IS.
The jihadist group has suffered a string of defeats to Kurdish forces since it was forced to withdraw from Kobane in January after a four-month battle.
Early this week, Kurdish Popular Protection Units (YPG) forces said they had captured a key town, Ain Issa, just 50km (30 miles) from the IS headquarters at Raqqa, days after seizing Tal Abyad and cutting a major supply line for IS.