Chinese pressure has forced North Korea to accept multiparty negotiations about North Korea's nuclear weapons program. These negotiations would involve the US, South Korea, Russia, Japan and China. Formerly, North Korea wanted one-on-one talks with the US and lots of economic and political concessions. China has lost patience with North Korea, which is helps prop up with economic aid (much of which is diverted to military use.) South Korea is now a major trading partner of China and China wants to solve the North Korea problem one way or another, and definitely does not want the north to have nukes.