South Korea's Vice Defense Minister Shin Beom-chul has received a briefing on key US nuclear assets, including a strategic bomber and "low-yield" weapons mountable on it, during a visit to a military base in the United States, his ministry said Friday.

His tour of Joint Base Andrews outside Washington, D.C., on Thursday (local time) followed North Korea's recent codification of an assertive nuclear policy that leaves open the possibility of a preemptive strike in case of a regime security threat.

Shin and Vice Foreign Minister Cho Hyun-dong were in the US capital to attend the allies' first high-level Extended Deterrence Strategy and Consultation Group (EDSCG) session since 2018. It is set to take place Friday.

"(Shin) was given a detailed briefing on US strategic assets, including the B-52 strategic bomber, which are to be deployed to the Korean Peninsula in a contingency, as well as kinds of low-yield nuclear arms and their operation," the ministry said in a press release.

"Low-yield" nuclear weapons refer to those that are less powerful than high-yield ones but still menacing given that they lower the psychological threshold for the use of nuclear arms as their employment will lead to relatively less human damage.

The defense ministry released a photo showing Shin looking at a wing part of a B-52 bomber, where a nuclear warhead can be fitted, in an apparent move to highlight the credibility of America's "extended deterrence," its commitment to mobilize a full range of its military capabilities to defend its ally.

"US officials in charge of extended deterrence stressed the US will definitely follow through on its extended deterrence commitment to using the whole range of its military capabilities for deterrence against North Korean threats," the ministry said.

Present at the base were senior US officials, including Vipin Narang, principal deputy assistant secretary of defense for space policy, and Deputy Assistant Secretary of Defense for East Asia Siddharth Mohandas.

Also on Thursday, Shin and Cho had talks with US National Security Advisor Jake Sullivan on security cooperation to cope with the North's evolving nuclear and missile threats, according to the ministry.

In addition, Shin met separately with Deputy Secretary of Defense Kathleen Hicks and Congressman Joe Wilson to discuss cooperation in strengthening the bilateral alliance and other issues. (Yonhap)