The United States is not considering a revision of the legal guidelines on the status of its 28,000 troops in South Korea, the nominee to become a top U.S.

defense official said Thursday, despite a renewed call for it in South Korea.

Mark W. Lippert, nominee for assistant secretary of defense fo Asian and Pacific security affairs, said in a Senate confirmation hearing that Washington wants continued flexibility in implementing the Status of Forces Agreement (SOFA) rather than a revision itself.

"The U.S.-ROK SOFA is a 'living document' that is constantly reviewed and kept current and fresh through the work of the Joint Committee, Special Joint Committee" and some 20 subcommittees, he said in a written response to a question on Seoul's possible request for talks on updating the SOFA.

The South Korean government has come under increased pressure to seek the renegotiation of the SOFA following a series of new reports on serious crimes by U.S. soldiers, including the rape of a young Korean girl last month.

Critics say the SOFA is still unjust and grants excessive legal protection for U.S. soldiers, leading to the recurrence of their crimes against locals.

At present, South Korean police have the right to take a U.S.

service member into custody only if the suspect is caught red-handed in such heinous crimes as murder or rape.

The SOFA was introduced in 1967 to govern the legal status of U.S. services members in the Asian nation and updated twice, in 1991 and 2001.

Lippert said the Joint Committee process has approved thousands of arrangements that effectively address the way in which the SOFA is implemented.

"This process has served both countries well over the years and continues to be the best path to address SOFA related issues," he said.

Seoul and Washington are scheduled to hold a meeting of the Joint Committee next week in Seoul.

Speaking to reporters last month, South Korea's Foreign Minister Kim Sung-hwan said his government will consider a push for the revision of the SOFA if it proves difficult to resolve the problem of South Korean police retaining custody of U.S. service members at an early stage in an investigation.

On North Korea, meanwhile, Lippert stressed the communist nation poses a "direct and serious threat" to the security of the U.S. and its allies.

He expressed worries not only over the North's own weapons development but also its proliferation activities.

"North Korea maintains a large, offensively postured conventional military; it continues to develop long-range ballistic missiles; it seeks to develop nuclear weapons; and it engages in proliferation of WMD (weapons of mass destruction) in contravention of international norms and law," he said. "What concerns me most is that this range of threats comes from a single actor who stands on the outside of the international community."

Lippert, who studied international relations at Stanford University, has served as an intelligence officer at the Naval Special Warfare Development Group.

He was senior foreign policy aide to Barack Obama when he was a senator. (Yonhap News)