Speaking on September 16 on the U.S. television network Fox, Gates said the United States would continue to pursue diplomatic and economic means to persuade Iran to halt its nuclear ambitions -- but that "all options" remain on the table.
The United States has accused Iran of trying to develop nuclear weapons, and has also suggested that it might consider military action to thwart Tehran's ambitions. Iran maintains that its nuclear program is peaceful.
As for Iraq, Gates said U.S. troops are likely to remain there for a "protracted period," but at a reduced level and with a more limited mission.
Gates did not give any troop numbers or a time scale. But he said the force would be a fraction of the size of the present deployment of over 160,000 personnel.
In the long term, Gates said U.S. troops would focus on border security, fighting terrorists, and training and equipping Iraqi security forces.
(AFP, AP)