US Secretary of Defense Mark Esper confirmed that all US troops withdrawing from northern Syria are expected to be relocated to western Iraq.
Esper told US reporters that, under current plans, about 1,000 soldiers would be redeployed to help stop the resurgence of Islamic State (IS).
US President Donald Trump has previously pledged to bring US troops home.
The US withdrawal from northern Syria paved the way for a Turkish military offensive against Kurdish fighters.
Both sides have accused the other of breaching a US-brokered ceasefire.