US-led forces carried out at least five air strikes today against Islamic State group fighters attacking the Syrian Kurdish town of Ain al-Arab, a monitoring group said.

The strikes hit IS fronts south and southeast of the town, known as Kobane by the Kurds, which the jihadists have been battling to take for more than two weeks, the Syrian Observatory for Human Rights said.

At least eight jihadists were killed in a strike that hit an IS tank east of the town, said the Britain-based Observatory, which relies on a wide network of sources inside Syria for its reports.

"Kurdish fighters on the front lines saw the bodies literally being thrown into the air" by the force of the strike, said Observatory director Rami Abdel Rahman.

Despite the strikes, the jihadists continued to shell the town on the Turkish border on Wednesday from positions as little as three kilometres (two miles) away.

Fierce fighting overnight killed nine Kurdish fighters and one IS militant, the Observatory said.

"Though they are fewer in number and are militarily worse equipped, the Kurdish fighters refuse to withdraw and are fiercely defending their town," Abdel Rahman said.

"For them, it is a matter of life or death."

Hundreds of Kurdish fighters are facing thousands of jihadists, who are armed with tanks, heavily artillery and 220mm multiple rocket launchers.

"The Kurds are armed with Kalashnikov rifles, Soviet-era DShK machineguns and RPGs," Abdel Rahman said.

Local Kurdish leader Anwar Muslim acknowledged the balance of forces favoured the jihadists.

"IS have brought in the weapons they seized from Mosul (Iraq's second city) and Tabqa airbase (in Syria's Raqa province)," he said.

IS seized large stocks of heavy weaponry from fleeing Iraqi troops when they captured Mosul in June. They took more when they overran the Syrian army garrison at Tabqa air base in late August.

Kurdish leaders have appealed to the US-led coalition battling IS to provide air support to the town's defenders.

"We are trying to push them (the jihadists) back with the help of the coalition's strikes. They are our common enemy," said Muslim.