BAGHDAD - US forces that crossed into Iraq as part of a pull-out from Syria do not have permission to stay and can only be there in transit, the Iraqi military said on Tuesday.
US Defense Secretary Mark Esper said, however, that Washington aimed eventually to bring the troops withdrawing from Syria back to the United States.
The Iraqi military statement contradicted the Pentagon's announcement that all of the nearly 1,000 troops withdrawing from northern Syria are expected to move to western Iraq to continue the campaign against Islamic State militants and "to help defend Iraq".
"All US forces that withdrew from Syria received approval to enter the Kurdistan Region so that they may be transported outside Iraq. There is no permission granted for these forces to stay inside Iraq," the Iraqi military said.
Esper said Washington's objective was for the troops not to remain in Iraq.
"The aim isn't to stay in Iraq interminably, the aim is to pull our soldiers out and eventually get them back home," Esper said at the Prince Sultan Air Base near Riyadh, Saudi Arabia.
Esper said the details had not yet been worked out on how long the US troops would stay in Iraq and he would be having discussions with his Iraqi counterpart on Wednesday.
It is unclear whether the US troops will use Iraq as a base to launch ground raids into Syria and carry out air strikes against Islamic State militants.
The additional US troops would add to the more than 5,000 American troops already based in the country, training Iraqi forces and helping to ensure that Islamic State militants do not make a comeback.
'Not a mercenary force'
Esper, speaking in front of a Patriot missile battery where he was meeting US troops, said Saudi Arabia had agreed to help underwrite the deployment to the kingdom. He did not provide details on what specifically Saudi Arabia had agreed to pay for.
The United States has deployed thousands of additional military forces in recent months to bolster Saudi defences, including an air expeditionary wing and air defense personnel.
That includes radar systems, Patriot missiles and support personnel to bolster Saudi Arabia's defenses after the largest-ever attack on the kingdom's oil facilities on Sept. 14.
Some experts have criticized President Donald Trump's administration for saying that Saudi Arabia will pay for the deployment of US troops to the Kingdom, suggesting it makes the U.S. military a mercenary force.
Trump has repeatedly said that Saudi Arabia would pay for the recent US deployments.
"We are not a mercenary force," Esper said.
"Mercenary forces do things for the pay, we are doing this (to).. help defend our allies, second to deter Iran so we don't have increasingly bad behaviour, and third defend the international rules based order," he added.