Economic Zone of up to . It also attempted to establish a military boundary zone around the islands claimed by South Korea along the NLL; however, this claim was rebuffed. With the collapse of the Soviet Union in 1991, North Korea wanted to establish a special economic zone and international port at Haeju, their southern deepwater port, to develop alternative trade opportunities. However, with the NLL enforced, access to Haeju required shipping to travel along North Korean coast for , often within of the shore. This prevents the development of Haeju as a large international port. Since September 1999, North Korea has claimed a more southerly "West Sea Military Demarcation Line" (also called "Inter-Korean MDL"). This maritime demarcation line is an extension line from the land boundary equidistant from the north and south mainlands, with channels to the north-west islands under UNC control, claimed to be based on international law delimitation decisions. According to a 2002 Korean Central News Agency article the NLL violates the Korean armistice agreement and the 12 mile territorial waters stipulated by the UN Maritime Convention. The article claims the Northern Limit Line is a root cause of armed clashes, and by insisting on the line the U.S. and South Korean seek to use it to spark military conflict. An earlier article reported that at meetings of the military armistice commission in December 1973 and July 1989 North Korea noted that future clashes were unavoidable unless a clear Military Demarcation Line was drawn in the West Sea, and urging the U.S. to negotiate such measures. On December 21, 2009, North Korea established a "peacetime firing zone" south of the NLL in waters disputed with South Korea. For many years North Korea has sold fishing rights in the area of the NLL to Chinese fishing companies, which South Korea regards as illegal fishing. South Korea's position The South Korean position from the 1970s has been: The NLL is an indispensable measure to administer the Armistice Agreement; The NLL is in the approximate mid-position between the islands and the North Korean mainland; North Korea acquiesced to the NLL until 1973, so implicitly recognized the NLL. In 2002 the Ministry of National Defense published a paper reasserting the legitimacy of the NLL, and arguing that North Korea's claims regarding NLL were groundless. The paper concluded that: The NLL has been the practical sea demarcation line for the past 49