Echoing military commanders, Secretary of State Condoleezza Rice said Sunday the United States could withdraw a significant number of troops from Iraq this year if Iraqi forces are able to assume greater control of the country's security. Just this past week, Defense Secretary Donald H. Rumsfeld declined to predict when US forces would be out of Iraq. President George W. Bush has said that decision would be up to a future US president and a future Iraqi government. "The level of the forces in Iraq will depend on conditions on the ground and the recommendations of the commanders," Rumsfeld told reporters at the Pentagon. He said he had not yet received a recommendation from Gen. George Casey, the top commander in Iraq, on whether or when to reduce the size of the force. There are now about 133,000 American troops in Iraq. Military officials have expressed hope they can reduce the number below 100,000 by year's end.