The White House statement said the timeframe would be "based on continued improving conditions on the ground and not an arbitrary date for withdrawal." President Bush has adamantly opposed setting such a deadline, saying it would only encourage insurgents in their efforts to destabilize the country.
In a sign of growing confidence as violence has declined, Iraqi officials have begun pressuring the United States to agree to a timeline to withdraw forces. Iraq has proposed requiring U.S. forces to leave five years after Iraqis take control of nationwide security, but that precondition could take years to meet, according to the Associated Press.
So far, the United States has handed over control of 10 of 18 provinces to Iraqi officials, the AP reported.
The United States sent approximately 20,000 more troops to Iraq in the spring of 2007 to clamp down on violence. Defense officials planned all along to bring the total number of troops back down to pre-"surge" levels by this summer.
The last of the extra five combat brigades that were sent to Iraq will finish withdrawing next week to bring the overall level down to about 140,000, Reuters reported.
U.S. and Iraqi officials are negotiating a broad security agreement to keep U.S. troops in Iraq beyond a U.N. mandate that expires Dec. 31. Earlier this month, al-Maliki and Iraqi national security adviser Mouwaffak al-Rubaie said that deal must include dates for troop withdrawals.
The debate over troop levels has become a key election issue for Sen. Barack Obama, D-Ill., who supported a timetable for withdrawing but later said he would immediately direct his commanders to end the war, and Sen. John McCain, R-Ariz., who backs the president's plans.
In addition, Defense Secretary Robert Gates has said officials are looking for ways to send more troops to Afghanistan where Taliban violence has been on the increase. A troop reduction in Iraq could help clear the way to send more forces there.
President Obama Set to Unveil Afghan War Strategy