US Defense Secretary Mr Donald Rumsfeld and US commander for Afghanistan General Tommy Franks acknowledged last night that American troops could be in Afghanistan for years.
The action is necessary to keep the country from reverting to "a terrorist training camp", they said.
"We are engaged in military-to-military relationships in a great many countries around the world so it does not surprise me that someone would say, 'Oh gosh, the military's going to be in Afghanistan for a long, long, time," Gen Franks said at the Pentagon. "Sure we will be."
Mr Rumsfeld talked of the phases of US military involvement in Afghanistan since the September 11th attacks on America, and said the current phase was aimed at preventing large concentrations of Taliban and al-Qaeda forces from regathering.
"We didn't go in there to leave in a way that allows it to turn back into a terrorist training camp, we went in there so that that would not happen," Mr Rumsfeld said.
"And the end-state is when the Afghan government has the capability to provide for its own security."