South Korea said Monday North Korea has violated the declaration they reached a decade ago by pursuing its nuclear weapons and testing program. Unification Ministry spokesman Chun Hae-sung said while Seoul remains willing to try to resolve reunification issues between the two countries through dialogue, the sinking of the South Korean naval ship Cheonan and Pyongyang's bellicose rhetoric demonstrates "North Korea has not changed from 10 years ago," Yonhap reported "We believe it's actually North Korea that has breached the spirits of the joint declaration, through its nuclear weapons development, nuclear tests, severance of inter-Korean dialogue and the Cheonan sinking," the South Korean news agency quoted Chun as saying. "If North Korea wants to improve the inter-Korean relations, it would have to take some acceptable steps, including apologizing for attacking the Cheonan and punishing responsible individuals, or abandoning nuclear weapons development."