South Korea's top security advisor says Seoul and Washington will work closely to ensure the success of their respective summits with North Korea.<br /> The head of the National Security Office Chung Eui-yong said the back-to-back summits "must succeed not only for the peace and stability of the region,... but also for that of the entire world."<br />Chung said his U.S. counterpart H.R. McMaster, agreed to continue discussing various ways to realize that goal.<br />The security advisors,.. along with their Japanese counterpart, met in San Francisco last weekend,... where they agreed to work closely for the success of the inter-Korean summit and the U.S.-North Korea summit. <br />