The Trump administration has not said how many US troops brought in to fight IS more than a decade ago remain in Iraq. Experts believe it's under 1,000, down from 170,000 at the height of the Iraq War.

The recent meetings on Iraqi security included the White House, Defense and State Departments, with Tom Barrack acting as a principal US voice on Iraq, four sources said. A close Trump ally, Barrack is the US ambassador to Turkey and special envoy to Iraq and Syria.

The administration has said publicly it's open to a bilateral security agreement with Iraq. The countries discussed a possible defence pact in the recent meetings, but it's still unclear how the agreement might be structured or what Iraqi Kurdistan's role might be.

Al-Zaidi touted the troop withdrawal during his visit to Washington last month. Al-Zaidi, who was elected in May, met Trump at the White House, as well as Hegseth and members of Congress.

"October 1 will mark a new day in the trajectory of the Iraqi state, as Iraq will be free of any foreign military presence," al-Zaidi's office said in a statement at the time.

The withdrawal will reduce the exposure of US troops in the Middle East who have been targeted by Iran during the war, analysts said. Tehran has attacked US bases across the region, including the base in Irbil.

But it will leave the Peshmerga security force and the rest of the region it helps protect even more vulnerable than before, said Jason Campbell, a former US defence official.

"The Peshmerga have been the frontline in the US and international war with ISIS," said Campbell, an expert at the Middle East Institute. "If the US moves forward with this, it'll make the Kurds perhaps the most vulnerable potential targets of Iran."

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