"I'd like to see a number of our forces move away from the Seoul area and from the area near the ... DMZ and be more oriented towards an air hub and a sea hub, with the ability to reinforce so there's still a strong deterrent, and possibly, with our improved capabilities of moving people, some of those forces come back home," he told the Senate Armed Services Committee.
Rumsfeld said the United States has been working on the plan for many months and would discuss it with the South Korean government soon.
The U.S. troops have been in Korea for more than 50 years, serving as a deterrent to a North Korean invasion. They would fight beside a force of more than 600,000 South Koreans and are largely poised as a counter-invasion force, swinging into action after the South Korean military has absorbed the first blow, according to military analysts.
With new nuclear tensions, recent warming of relations with North Korea, and a number of high-profile criminal cases and accidents involving American military personnel and Korean civilians, anti-U.S. sentiment is on the rise in South Korea.
Korea Gallup conducted an opinion poll indicating that more than 53 percent of South Koreans surveyed said they disliked the United States, up from 15 percent in 1994. The percentage of those who said they liked the United States fell from nearly 64 percent in 1994 to 37 percent, the Washington Post reported in early January.
North Korea broadcast a New Year's message in January calling on "all the Koreans in the North and the South and abroad" to confront the United States. "It can be said that there exists on the Korean Peninsula at present only confrontation between the Koreans in the North and the South and the United States," the message said.
In October, the United States said North Korea admitted to having produced and stockpiled enriched uranium in contravention of a 1994 agreement under which it had promised to abandon its nuclear program -- albeit plutonium-based -- in exchange for fuel oil and two light-water reactors.
The light-water reactor project was supposed to be finished in 2003 but has been delayed by construction problems at least five years. U.S. President George W. Bush labeled North Korea as one of the members of the "axis of evil" in January 2001.