A Kurdish official and an activist group say Kurdish fighters have advanced in the contested northern Syrian town of Kobani after heavy clashes with the Islamic State group.

Nawaf Khalil, a spokesman for the Kurdish Democratic Union Party, says Kurdish fighters advanced Saturday in six neighborhoods and have besieged the IS-held Cultural Center east of town.

The Britain-based Syrian Observatory for Human Rights says the main Syrian Kurdish force, known as the People's Protection Units, or YPG, killed several IS fighters.

The IS group began its Kobani offensive in mid-September, capturing parts of the town as well as dozens of nearby villages.

Kurdish forces have gradually pushed the extremist group back in recent weeks with the help of U.S.-led coalition airstrikes.