The United States and South Korea reached on Friday an agreement to move the American military headquarters and all American troops out of the capital Seoul, the Pentagon said.

The two countries agreed to a plan to relocate all 8,000 US troops from the Seoul metropolitan zone to the Pyongtaek area, about 80 kilometers south of the capital, by December 2008, the Pentagon said.

"This relocation agreement helps us meet our enduring commitment" to the defense of South Korea and to the security and stability of the region, Richard Lawless, the US deputy under secretary of defense for Asia Pacific affairs, said in a statement.

Washington and Seoul, allied to each other since the 1950-53 Korean War, agreed last year to move the sprawling Yongsan garrison from central Seoul to a site well south of the capital.

The US announced last month that it planned to withdraw one third of its 37,500 troops from South Korea as part of a global force realignment. In May, the Pentagon said it was shifting 3,600US troops from South Korea to duty in Iraq.