The government of Syrian President Bashar al-Assad said on Wednesday it is willing to help Baghdad in the fight against "terrorism", a day after jihadi fighters overran Iraq's second-largest city Mosul.

"The foreign-backed terrorism that our brothers in Iraq are facing is the same that is targeting Syria," said the foreign ministry.

Damascus is "ready to cooperate with Iraq to face terrorism, our common enemy", it said in a statement.

The Islamic State of Iraq and the Levant is a radical jihadi group operating in Iraq and Syria. It aims to establish an Islamic emirate stretching across the two countries' borders.

ISIL militants spearheaded a jihadi offensive on Tuesday that claimed the province of Nineveh and its capital Mosul, as well as other parts of northern Iraq.

In Syria, ISIL controls large swathes of the oil-rich province of Deir Ezzor, which borders Iraq.

"This terrorism is a threat to peace and security in the region and the world," said the Syrian ministry, calling on the UN Security Council "to decisively condemn these terrorist and criminal acts, and to take action against the countries supporting these groups."

In Syria, the regime has systematically branded peaceful opponents, rebels and jihadists alike as "terrorists" backed by the Gulf.

AFP