Arab foreign ministers meeting in Cairo on Sunday are expected to issue a resolution backing Iraqi and US efforts to confront Islamic State insurgents who have overrun large areas of Iraq and Syria and declared a cross-border caliphate, diplomats said.

An Iraqi diplomatic source said Baghdad had proposed a draft resolution that would endorse its efforts to confront the jihadi militants and condemn the group's actions as war crimes and crimes against humanity.

Other diplomatic sources said the Arab League would agree a resolution endorsing the US aerial campaign against the group. Egypt's official Mena news agency quoted a source saying the ministers would agree to coordinate with the US.

It was not immediately clear if Washington would be named in the final text as the foreign ministers were expected to hammer out the details over the ensuing few hours.

However, the draft also endorses a UN Security Council resolution passed last month that urges member states to "act to suppress the flow of foreign fighters, financing and other support to Islamist extremist groups in Iraq and Syria".

Diplomatic sources said backing for Iraqi efforts and the UN resolution could be read as offering tacit support for U.S. action even if the United States is not named in the final text.

President Barack Obama declared last week the US was ready "take out" leaders of Islamic State and said Nato allies were prepared to join military action against a movement he labelled a major threat to the West.

US warplanes carried out four strikes against Islamic State militants threatening western Iraq's Haditha Dam early on Sunday, witnesses and senior officials said, broadening Washington's campaign against the fighters.

Obama would like Gulf states to consider military action, but also to support Sunni Muslim moderates in Iraq and Syria who could defeat the appeal of Islamic State. He also wants Islamic State's sources of funding cut off, a point on which the Iraqi draft resolution touches.

US Secretary of State John Kerry is to travel to Saudi Arabia and Jordan in the coming week for talks with Gulf leaders to determine whether they are prepared to back up their anti-jihadist rhetoric with action. - Reuters