Senior defense officials from the US and South Korea met in Seoul to discuss and establish guidelines for their joint response to any nuclear threat from North Korea. The guidelines emphasize the importance of maintaining a credible and effective nuclear deterrent policy and posture. The meeting comes amid concerns over North Korea's continued development of nuclear arms and delivery systems, with some South Korean politicians calling for the development of their own nuclear weapons. The guidelines also outline procedures for consultation and coordination in the event of a North Korean nuclear crisis.