"The hope is they can come home before Christmas," Geoff Morrell, the Pentagon press secretary, said of the decision by Gen. David H. Petraeus, head of Central Command overseeing U.S. forces in the Middle East and Central Asia.
The reason is dramatically lower violence there, officials say.
The plan accelerates the withdrawal from Iraq of a 101st Airborne Division brigade of 3,500 to 4,000 troops that will not be replaced, The Washington Post reported.
The departing brigade has served in Baghdad, where attack levels have plunged. Its troops will serve only a 13-month tour, instead of the expected 15 months, before returning to their home base at Fort Campbell, Ky.
Another brigade from the 10th Mountain Division that was scheduled to go to Iraq in its place will instead deploy to Afghanistan, as announced earlier.
Defense Secretary Robert M. Gates says further increases in U.S. troop levels in Afghanistan will be contingent upon further withdrawals from Iraq next year.
American commanders in Afghanistan say they need three more brigades and thousands of support forces to combat a growing insurgency.