The attacks on two key oil installations were claimed by Yemen's Huthi rebels, but the US has denied they originated from the war-torn state.

Some US officials are investigating whether missiles were actually launched from Iraq or Iran, but Baghdad on Sunday denied its territory was used for the strikes.

On Monday, Prime Minister Adel Abdel Mahdi told Pompeo that Baghdad's aim was to "prohibit Iraqi territory being used to wage attacks against any neighbouring, brotherly or friendly country".

According to a statement from the premier's office, Pompeo told Abdel Mahdi that information gathered by the US "confirms" that Iraqi land was not used in the latest attacks.

Iraq is home to several Iran-backed militias and paramilitary factions, placing it in an awkward situation amid rising tensions between its two main sponsors, Tehran and Washington.

Iraq has called for its territory to be spared any spillover in the standoff between the US and Iran, which has included a series of attacks on shipping in sensitive Gulf waters.

But raids on bases belonging to Iraqi Shiite paramilitary groups linked with Iran attributed to Israel have sparked fears of an escalation.

There have been no military consequences so far, although the strikes have heightened tensions between pro-Tehran and pro-Washington factions in Iraq's political class.

Baghdad has recently moved to repair ties with Saudi Arabia, a key US ally -- much to Iran's dismay.

Riyadh announced that a major border post on the Iraqi frontier would reopen in mid-October, after being closed for almost three decades.