years and was confirmed and validated by the 1992 South-North Basic Agreement; Until a new sea nonaggression demarcation line is established, the NLL will be resolutely maintained like the ground Military Demarcation Line, and decisive responses will be made to all North Korean intrusions; Any new sea nonaggression demarcation must be established through South-North discussions, and the NLL is not the subject of negotiation between the US or UNC and the North; North Korea's claims violate the Armistice Agreement and are not compatible with the spirit and provisions of international law. On October 4, 2007, South Korean President Roh Moo-hyun and North Korean leader Kim Jong-il addressed the issue of NLL disputes in a joint statement: However the following South Korean President Lee Myung-bak rejected this approach, describing the NLL as a "critical border that contributes to keeping peace on our land." South Korean academics at the Korea Maritime Institute argued in 2001 that the legal situation between the two Koreas is a special regime governed by the armistice agreement, and not usual international law such as the Law of the Sea. Consequently, the NLL is subject to political agreement between the two Koreas, rather than international law remedies. On November 1, 2018, a buffer zone was established near Yeonpyeong Island. The U.S. position The United States government position, separate from the United Nations Command, is not clearly expressed. When asked about the NLL, United States government representatives usually refer questioners to the UNC in South Korea. In February 1975, Secretary of State Henry Kissinger wrote in a confidential cable, now declassified, that the "Northern Patrol Limit Line does not have international legal status ... Insofar as it purports unilaterally to divide international waters, it is clearly contrary to international law and USG Law of the Sea position." Earlier in 1973 a "Joint State-Defense Message" to the U.S. Embassy in Seoul stated that South Korea "is wrong in assuming we will join in attempts to impose NLL", and the U.S. Ambassador told the South Korean government that the North Korean territorial sea claim created a zone of uncertain status with respect to the NLL. In November 2010, following the North Korean Shelling of Yeonpyeong, President Barack Obama said the U.S. stood "shoulder to shoulder" with South Korea and condemned the attack, but did not specifically address the NLL. Border clashes Clashes between North and South Korean fishing boats and naval