South Korean Foreign Minister Yun Byung-se said on Saturday that North Korea's nuclear capability had grown to a 'considerable level' and tougher sanctions and greater pressure were needed, Yonhap news agency reported. Yun made the comments at a meeting to discuss the response to the North's fifth, and biggest, nuclear test, conducted on Saturday. The North said it had mastered the ability to mount a nuclear warhead on a ballistic missile.
