The troops will be moved farther south, a joint statement said after two days of talks. The redeployment will remove U.S. military bases from the Korean front line for the first time since the end of the 1950-53 Korean War.
The statement gave no timetable for the withdrawal. Even after the redeployment, U.S. troops will continue to train north of Seoul and close to the DMZ, it said.
In April, Defense Secretary Donald H. Rumsfeld said U.S. troops stationed near the Korean DMZ could be shifted south, moved to other countries in the region or even brought home under a global realignment of U.S. troops.
Pentagon officials have characterized the proposed moves as part of a wide-ranging review of American military posture that aims to match deployments with current, rather than past, threats. Postings in Europe that have been maintained since World War II are also being evaluated.
For half a century, the U.S. presence near the DMZ has symbolized the U.S.-South Korean military alliance and Washington's commitment to deterring hostilities on the divided peninsula. Tension remains high because of North Korea's suspected development of nuclear weapons.
About 37,000 U.S. troops are stationed in South Korea, most of them between the DMZ and Seoul, which lies 37 miles south of the border and within artillery range of North Korea.
"When (the redeployment from the DMZ) is fulfilled requires further discussions," said South Korean Assistant Defense Minister for Policy Lt. Gen. Cha Young-koo. "But you can see a broad picture of where we are headed."
Cha led the South Korean side in talks with the Americans led by Deputy Assistant Defense Secretary for East Asia Richard Lawless.
On Tuesday, Deputy Defense Secretary Paul Wolfowitz said the Pentagon must modernize its troops to better counter a potential North Korean attack. He hinted that could mean smaller, more mobile forces working at greater distances from their opponents.
Rumsfeld's comments in April had spawned uneasiness in South Korea, which worries that reductions would put it at greater risk of a North Korean attack. President Bush and South Korean President Roh Moo-hyun met in May and reconfirmed their military alliance.
Last week, the U.S. military said it would spend an additional $11 billion over the next three years to strengthen its forces in South Korea. The plan included improvements to intelligence collecting and weapons upgrades as well as deployment of special, swift-action forces.
North Korea condemned that plan as a preparation for war.
Washington also wants North Korea to scale down its massive deployments of conventional troops near the DMZ.
Thursday's statement said the United States and South Korea remained committed to "improve the combined defense," but wanted to structure "U.S. forces in a manner that further promotes regional stability."
The two sides will first consolidate U.S. troops near the DMZ into two major bases, Camp Casey and Camp Red Cloud, north of Seoul. That process could begin as early as this year.
In a second phase of realignment, the troops will move to "key hubs south of the Han River," which bisects Seoul, the statement said.
U.S. officials have worried that their troops may be too close to the border. That means in an attack by the North, the Americans would either be killed in large numbers or forced to withdraw south before regrouping for a counteroffensive.
The U.S. forces also are close to urban areas, causing tension with residents. In June 2002, two girls were hit and killed by a U.S. military vehicle near the border, and their deaths triggered large demonstrations.
Most of the U.S. troops on the ground in South Korea — more than 28,000 — are Army soldiers. Nearly 900 are Air Force members. The Navy and Marines Corps comprise about 500 servicemembers there.
The contingent in South Korea is the second-largest U.S. posting; some 41,000 troops are in Japan. Other large foreign stations include Germany (68,700), Italy (12,400) and Britain (10,200).
Meanwhile, Asian leaders said Thursday that alleviating North Korean poverty was the key step toward disarming the nuclear standoff with the communist country and urged the region to come forth with economic aid.
The urging comes after a recent U.S. delegation to North Korea said they were told by officials that the country's nuclear weapons as well as its nuclear facilities and materials will be on the bargaining table if negotiations begin with outside countries.
But during the same trip, North Korean officials also warned they are ready to build more atomic bombs if needed, the U.S. delegation reported.
During talks in April in Beijing, North Korea indicated to U.S. and Chinese officials that might surrender its nuclear program in exchange for economic benefits.