Islamic State (ISIS) group fighters executed at least 20 Syrian Kurds, among them women and children, in a village south of the border town of Kobane on Thursday, a monitor said.

"Islamic State forces shot dead at least 20 people in the Kurdish village of Barkh Butan, including women and children and residents who had taken up arms to fight," the Syrian Observatory for Human Rights said.

ISIS launched a surprise attack on Kobane on Thursday, using at least two suicide car bombs and clashing with Kurdish forces.

Kobane, on the border with Turkey, is an important symbol in the battle against the jihadists, having been secured by Kurdish militia with U.S.-led air support in January after four months of ferocious fighting.

ISIS fighters briefly entered Barkh Butan in the morning but withdrew after coalition airstrikes and the arrival of Kurdish forces, Observatory director Rami Abdel Rahman said.

At least five jihadists were killed in clashes with residents, the Observatory said.

Arin Shekhmos, a Kurdish activist in northern Syria, confirmed the executions.

"IS(IS) committed a massacre in Barkh Butan, killing some 20 civilians," Shekhmos said.