BEIRUT (AFP) - A female Kurdish fighter carried out a suicide bomb attack against extremists from ISIS (Islamic State in Iraq and Syria) outside the embattled Syrian border town of Kobane on Sunday, a monitor said.

The Syrian Observatory for Human Rights said the woman blew herself up at an Islamic State position east of the city, killing a number of militants who have surrounded Kobane and are battling to seize it.

"The operation caused deaths, but there is no confirmed number," Observatory director Rami Abdel Rahman said. He said it was the first reported instance of a female Kurdish fighter carrying out a suicide bombing against the ISIS, which has itself often favoured the tactic.

ISIS began its advance on Kobane, Syria's third largest Kurdish town, on September 16, seeking to cement its grip over a long stretch of the Syria-Turkey border.

The fighting around the town, also known as Ain al-Arab, has prompted a mass exodus of residents from the area, with some 186,000 fleeing across the border into Turkey.