Activists say Islamic State militants have beheaded nine Kurdish fighters, including three women, captured in clashes near the Syria-Turkey border.

The Britain-based Syrian Observatory for Human Rights said Wednesday that the nine Kurds were captured during fighting over the northern Syrian town of Kobani, also known as Ayn Arab.

There have been fierce clashes around Kobani since mid-September, when the Islamic State group launched an assault to seize the area.

The Observatory also says that dozens of militants and Kurdish fighters were killed in clashes overnight.

Images posted on social media networks show women's heads placed on a cement block, said to be in the northern Syrian city of Jarablous, held by militants. The photos could not be independently verified but corresponded to The Associated Press' reporting of the event.