Damascus, Oct 13 (IANS): Kurdish fighters have advanced against the Islamic State (IS) terrorist group in the southern rim of Syria's northern city of Kobane, killing 13 IS militants, a monitoring group said Monday.

Intense battles have continued in the southern part of Kobane, also known as Ayn al-Arab, where Kurdish fighters of the People's Protection Units (YPG) unleashed a counter-offensive against IS positions in that part of the predominantly Kurdish town, stripping them of two sites the IS had managed to establish a foothold at, Xinhua reported citing the Syrian Observatory for Human Rights (SOHR).

Clashes also continued in the eastern districts of the strategic city near the border with Turkey amid slight advances of the YPG, according to the London-based group, which relies on a network of activists on the ground.

Meanwhile, the US-led anti-terror coalition struck five IS positions in the southern parts of Kobane early Monday, the SOHR said without elaboration.

As the intense clashes raged on, over 500 Kurdish families fled Kobane toward Syria's northern province of Hasaka, the pan-Arab al-Mayadeen TV said Monday.

Also Monday, the local al-Watan daily quoted Kurdish sources in Kobane as stating that the US strikes against IS positions have been useful over the past three days "thanks to the information provided by informants among the IS ranks".

It said the IS in Kobane was infiltrated by informants who were providing the US-led coalition with "precise information" via a third party about the movements and gatherings of the group.

The paper said that Kurdish fighters in the IS had been important sources of information that prevented the terror group from capturing the entire city so far.

The IS has also executed 12 Kurdish fighters among its ranks, accusing them of providing viable information about the group's military plans, according to the paper.

The SOHR said earlier that IS fighters had captured over 40 percent of the city, adding that the weeks-long battles have killed over 500 people, the majority of whom were fighters from both sides.

Kobane has been subject to ferocious attacks by IS militants over the past three weeks. The IS fighters have succeeded in capturing hundreds of Kurdish villages around the city, forcing tens of thousands of people to flee to Turkey.

The capture of the city would enable the IS to link its self-declared capital of al-Raqqa province with Kobane and stretch its territory to areas bordering Turkey.

Syrian Kurds have reached a deadlock in their fight against the IS militants, who have repeatedly tried to storm Kurdish-dominated Syrian areas. Accounting for some 15 percent of Syria's 23 million residents, the majority of Kurds live in the northern part of the embattled country.