"The US-led international coalition to fight terrorism launched air strikes on Wednesday morning against (local) headquarters of the Islamic State in Albu Kamal on the Iraqi border," state news agency SANA reported.

"US and allied planes also launched raids on the outskirts of Ain al-Arab town in northern Aleppo," the agency added.

The report came after the Syrian Observatory for Human Rights monitoring group reported 13 air strikes on Albu Kamal.

The area in eastern Syria, on the Iraqi border, was also targeted by the coalition on Tuesday, when it began its first air strikes on Syrian territory.

The Observatory also reported strikes around midnight Tuesday night near Ain al-Arab, known by the Kurds as Kobane, which the Islamic State group has been battling to capture for a week.

The Britain-based monitor said planes crossed into Syria from Turkish airspace and hit IS positions and supply lines west of the border town.

But Turkey denied that either its airspace or air bases on its territory had been used in the strikes.

"The answer is clear: Neither the (Turkish) airspace nor the Incirlik (air base) were used," an official told AFP in Ankara.

Incirlik, in southern Turkey, is used by both US and Turkish forces.

Turkey has so far remained hesitant to play an active role in the US-led coalition to defeat IS militants, though it has expressed abstract support for its mission.

At least 120 jihadists from IS and Al-Qaeda in Syria, as well as eight civilians, have been killed in the strikes so far.

The raids around Ain al-Arab come a week after IS militants began a fierce assault against what is Syria's third-largest Kurdish town.

IS seized at least 64 villages surrounding the strategic town in within days as it advanced towards the town, prompting more than 130,000 civilians to flee into Turkey.

In recent days, Kurdish fighters have managed to slow the jihadist advance.