(Kabul) -- Defense Secretary Robert Gates says U.S. troops could leave Afghanistan before 2011. During a joint press conference with Afghan's defense minister in Kabul, Gates reassured U.S. troops their efforts and those who had fallen will not be forgotten.

Gates said early removal of troops would be "conditions-based" and would rely on other members of NATO sending more troops to train the Afghan army. By fall of 2011, the Afghan National Army is expected to increase its numbers to 171-thousand troops, and the police force to 134-thousand.

Defense Secretary Robert Gates told the troops about their sacrifices.

Gates says he has done his job for the troops.