Mursitpinar, Turkey-Syria border: Heavy shelling rocked Kobane as Islamic State militants continued their assault on the besieged Syrian Kurdish border town, the boom of mortars, crack of gunfire and the wail of ambulances echoing across the brown, rural valley.

Three US air raids overnight failed to halt the insurgents' advance, and the Kurdish fighters left inside Kobane say they fear IS plans to stage a symbolic attack on the town's mosque on the eve of the Islamic feast day of Eid al-Adha.

"Da'esh [Islamic State] is now surrounding Kobane on three sides and is just one to two kilometres from the city centre," said Ismet Sheikh Hassan, a commander with the YPG Kurdish militia.

"They vowed to take the mosque in the centre of the town – we have stopped them so far but they are pushing into the city," he says. "We have been fighting them for 20 days . . . we may run out of ammunition in the coming days."