US Defense Secretary Donald H. Rumsfeld's talks in South Korea on the future shape of the US-South Korean defense alliance made two things clear: The Koreans want more control over their own defense, and Washington wants to give it. Rumsfeld used two appearances Friday to highlight and applaud South Korea's vibrancy and stability, and he stressed similar themes in closed-door meetings with President Roh Moo-hyun, Defense Minister Yoon Kwang-ung and other officials, according to aides. In Rumsfeld's view, South Korea has developed to the point where it should assume more defense responsibility - the sooner, the better - and the South Koreans say that's their goal. Neither side, however, has worked out the details or decided over what period of time the transition should happen. In a "town hall" meeting with about 1,000 US troops at the Yongsan headquarters of US Forces Korea, Rumsfeld noted that the South Korean military has recently assumed responsibility for six missions previously performed by American troops, and that they will take over four more in the months ahead. "As that happens, we'll see them play a larger and larger role ... and the United States will be able to play a somewhat lesser role," he said. "How that will evolve over time depends on a variety of things," including the outcome of diplomatic efforts to end North Korea's nuclear programs. Rumsfeld affirmed the US commitment to maintain a troop presence in South Korea - albeit at lower levels - and he bristled at a suggestion that South Koreans increasingly believe they would be better off without the Americans. Rumsfeld compared the difficulties the United States faces in its wars in Iraq and Afghanistan to the darker days of the 1950-53 Korean War, in which more than 30,000 US troops died. He noted that many had asked then why the United States should sacrifice in battle on the Korean peninsula. "Today the answer to the question is clear," he said, noting that South Korea has grown into an economic powerhouse and a stable democracy. "The Republic of Korea, an impoverished and devastated nation over a half-century ago, now has one of the world's most powerful economies and is an important democracy with a large and increasingly capable armed force," Rumsfeld told a Seoul news conference following 2 1/2 hours of annual defense talks. These changing circumstances make it important for South Korea to take on a greater share of the burden for its own defense, Rumsfeld said - adding that South Koreans should not dismiss the value of US support. "The United States of America has invested the lives of a great many Americans in helping the Republic of Korea to be free," he said. "We are a part of this alliance at the request of the Republic of Korea's government." In a joint statement issued after their talks, the US and South Korean defense officials welcomed North Korea's promise in six-country talks to abandon its nuclear weapons development. But he said concerns remain. "Both sides noted that North Korea's continued development of weapons of mass destruction and long-range missiles, along with the danger of proliferation of those weapons and technologies, are causes of significant concern," the communique said. Rumsfeld and Yoon agreed to "appropriately accelerate discussions on command relations and wartime operational control." Seoul has said it wants to take control of the joint command of US as well as South Korean troops here during wartime, which traditionally has been a US control. The Pentagon has begun pulling thousands of US troops out of South Korea, where it has maintained a contingent of about 37,000 troops for decades amid concerns that the communist North might attempt to reunite the two Koreas by force. Gen. Leon J. LaPorte, commander of US forces in Korea, told reporters Thursday that by the end of this year, 8,000 of the 12,500 troops designated for withdrawal will have left South Korea. Rumsfeld was asked during Friday's news conference whether Washington wanted to make further cuts. "I know of no plans to do that," he replied.