US Central Command said American bombers, fighter aircraft and drones struck five times south of Kobane, damaging or destroying an IS training camp, a building and two vehicles.

The strikes also hit two IS combat units, one small and the other large, said the command, which oversees US military operations in the region.

"US Central Command continues to monitor the situation in Kobane closely," it said. "Indications are that Kurdish militia there continue to control most of the city and are holding out against ISIL."

ISIL is an alternative acronym for the Islamic State group.

IS forces have been advancing on Kobane, also known as Ain al-Arab, whose fall would give the jihadist group control over a long stretch of the Syrian-Turkish border.