Iraq appears to have closed the door on America's attempt to keep US troops, leaving neighbouring Syria, there.
Iraqi defence minister Najah al-Shammari said they were only "transiting" Iraq and would leave within four weeks, heading either to Kuwait, Qatar or the United States.
Mr al-Shammari spoke after meeting US Secretary of Defense Mark Esper, who earlier this week had said the American forces from Syria would remain in Iraq to fight the so-called Islamic State (IS) group.
Iraqi's military said they did not have permission to do so.
It follows in the wake of President Donald Trump's order for US troops to leave Syria.
They were allied to the Kurdish-led Syrian Democratic Forces for five years - they fought together to bring down IS in Syria.
US troops have continued to pull out of the north of the country after Turkey's invasion into the area around the border.
Meanwhile, Mr Trump has said he will lift sanctions on Turkey after the NATO ally agreed to permanently stop fighting the Kurdish forces.
Making the announcement, Mr Trump defended his decision, saying it is not the job of the US military "to police the world".
"Other nations must step up and do their fair share," he said.
"Today's breakthrough is a critical step in that direction."
Speaking at the White House, Mr Trump also said: "Let someone else fight over this long, blood-stained sand."