Saudi-owned al-Arabiya television said Saudi Arabia had deployed 30,000 soldiers to its border with Iraq on Thursday after Iraqi forces abandoned the area, but Baghdad denied pulling forces back and said it remained in full control of its frontier.

Saudi Arabia, the world's top oil exporter, shares an 800-km desert border with Iraq, where Islamic State insurgents and other Sunni Muslim militant groups seized towns and cities in a lightning advance last month.

The U.S.-allied kingdom overcame its own al Qaida insurgency almost a decade ago and is wary of any new threat from radical Sunni Islamists.