"The international community has imposed broad and far-reaching sanctions on North Korea (DPRK) through both the United Nations and national measures, but implementation has been uneven globally and in cases has diminished over time. An important challenge has been encouraging nations with substantial trade links to North Korea--particularly China, but also a range of nations that service as transshipment points for North Korean goods or that have financial institutions that deal with North Korean entities--to implement U.N. sanctions. Different nations interpret U.N. sanctions differently, and the degree to which they are followed hinges on a country's overall policy toward the North. The DPRK is conditioning the resumption of talks on its nuclear program on the lifting of U.N. sanctions. The March 26, 2010 sinking of the South Korean naval ship, the 'Cheonan', initially caused key players in North Korean diplomacy to back away from pushing implementation until the Security Council decided on its response to the incident. After that, the Cheonan sinking helped to coalesce country actions toward North Korea and was a turning point in implementing sanctions. In response to the attack, some countries, such as the United States and South Korea, imposed even stronger measures than required under U.N. Security Council resolutions."
CRS Memorandum, October 8, 2010
U.S. Dept. of State, Foreign Press Centers: http://www.fpc.state.gov/