Turkish airstrikes destroy 'Islamic State buildings' in Syria

Three buildings used by the Islamic State group in north Syria were destroyed by Turkish airstrikes on Friday, the military said, as the cross-border offensive continued.

The structures in Arab Ezza and al-Ghundura were struck by warplanes involved in an unprecedented military operation launched by Ankara last week.

On Thursday the Turkish army said it had cleared "terrorist elements" out of three villages west of Jarabulus - a border town taken from Islamic State militants by Turkish-backed Syrian rebels last week.

The villages - Zavgar, Tal al-Agbar and Kiliyeh - lie in territory where Turkish-backed forces have been fighting IS.

Turkey says it has cleared dozens of villages of "terrorists" since the start of its unprecedented Syria operation on August 24.

Meanwhile, the Pentagon said IS in Syria is about to lose access to Turkey's porous border, a vital step in blocking foreign fighters from replenishing the jihadists' thinning ranks.

According to Pentagon spokesman Captain Jeff Davis, IS now retains control of only about 25 kilometres (15 miles) of border with Turkey along an area to the east of the small Syrian town of Al-Rai.

"This is the only area with which ISIL has free communication with the outside world, where it touches a border," Davis said, using an IS acronym.

"This is about to be closed. We are very close to achieving this."

Turkey's incursion into Syria has brought a new element to an already complex situation in the war-torn country, as Ankara has also targeted US-backed Kurdish fighters.