South Korean Defense Minister Lee Jong-sup has touted a new Seoul-Washington security document as what can be called the allies' "second" mutual defense treaty given that it entails America's reinforced deterrence commitment to the Asian ally.

Lee made the remarks in a contribution to the local daily Maeil Business News Korea on Monday, referring to the Washington Declaration that President Yoon Suk Yeol and his US counterpart, Joe Biden, adopted during a White House summit last week.

The declaration included a series of deterrence measures against growing North Korean threats, including a plan to launch the Nuclear Consultative Group on nuclear and strategic planning issues, and a US pledge to enhance the "regular visibility" of strategic assets to Korea, such as a nuclear ballistic missile submarine.

"Given that it is an upgrade of the 1953 South Korea-US mutual defense treaty -- based on conventional weapons -- into a mutual defense concept including the nuclear (assets), the meaning of this declaration is great to the extent that it can be called a second South Korea-US mutual defense treaty," he wrote.

Touching on the NCG, the minister said that it laid the foundation for an "extended deterrence" mechanism under which Seoul and Washington will work together rather than the latter unilaterally providing it to the ally.

Extended deterrence refers to Washington's stated commitment to using the full range of its military capabilities to defend its ally.

"It is a commitment that (the US) will work together with South Korea in the overall extended deterrence (processes), including information sharing, consultation, planning and execution," Lee said.

Lee also attached "great" meaning to the planned visit to Korea of the SSBN, which he described as one of the three key US nuclear assets, which is known for its survivability and covert operational capabilities.

"The SSBN visit to the Korean Peninsula would show that the US' most credible extended deterrence capability is in operation regularly for the protection of the Republic of Korea," he said, referring to the South by its official name. (Yonhap)