Richard Lawless, US deputy assistant secretary of defense for East Asia, and South Korea's assistant defense minister for policy, Cha Young-Koo, were engaged in talks scheduled to last two days, the Defence Ministry said.

The United States deploys 37,000 troops in South Korea, nearly 15,000 of them with the 2nd Infantry Division north of Seoul near the border with the Stalinist North.

"We are opposed to the early relocation of key front-line bases like the 2nd Infantry Division. The issue can be discussed only after the nuclear crisis is over," a defense ministry official told AFP.

The talks are taking place following massive anti-US protests last year and calls from South Korea President Roh Moo-Hyun for a more balanced bilateral relationship.

However, indications that Washington may reduce its troop presence or withdraw forces from the border have alarmed the South Korean government.

Prior to the launch of the talks, Cha told Yonhap news agency that "all pending issues" would be discussed.

"We will do our best to search for a 'win-win' strategy, beneficial to both countries," he said.

Lawless said in a statement released on his arrival in Seoul that the United States would seek ways to strengthen the alliance and develop equal relations while reviewing US military positions around the world.

"These talks are about ways to improve our alliance. Together we will look for ways to make it a more capable alliance, a more equal alliance, and an alliance that is less intrusive in the daily lives of the Korean people," he said.

Hints that Washington wants to move its troops south of Seoul and out of harm's way from North Korea's artillery would be a major switch of alignment.

South Korea considers the deployment of US bases near the border with North Korea as a "tripwire" that would trigger automatic US involvement in any new conflict on the Korean Peninsula.

SPACE.WIRE