The Bombardment of Yeonpyeong (연평도포격사건) was an artillery engagement between the North Korean military and South Korean forces stationed on Yeonpyeong Island on 23 November 2010. Following a South Korean artillery exercise in disputed waters near the island, North Korean forces fired around 170 artillery shells and rockets at Yeonpyeong Island, hitting both military and civilian targets. Shelling caused widespread damage on Yeonpyeong. South Korea retaliated by shelling North Korean gun positions. In total, between four and 20 people (military personnel and civilians) were killed on both sides and approximately 40–55 people were wounded. The North Koreans subsequently stated that they had fired in response to South Korean artillery firing into North Korean territorial waters. The incident caused an escalation of tension on the Korean Peninsula and prompted widespread international condemnation of the North's actions. The United Nations declared it to be one of the most serious incidents since the end of the Korean War, and by 18 December, former US ambassador to the UN Bill Richardson said tensions had escalated to become "the most serious crisis on the Korean peninsula since the 1953 armistice, which ended the Korean War". Background A western maritime line of military control between the two Koreas was established by United Nations Command (UNC) in 1953, called the Northern Limit Line (NLL). According to Time, "The North does not recognize the border that was unilaterally drawn by the United Nations at the close of the 1950–53 Korean War." Under the provisions of the armistice, five Northwest Islands are specifically designated to remain under the jurisdiction of the United Nations. The countries' western maritime boundary has long been a flash point between the two Koreas. North Korea did not dispute or violate the line until 1973. The NLL was drawn up at a time when a three-nautical-mile territorial waters limit was the norm, but when in the 1970s a twelve nautical mile limit became internationally accepted, the implementation of the NLL prevented North Korea, in areas, from accessing, arguably actual or prospective, territorial waters. Later, after 1982, it also hindered North Korea establishing a United Nations Convention on the Law of the Sea Exclusive Economic Zone to control fishing in the area. In 1999, North Korea drew up their own line, the "West Sea Military Demarcation Line" which claims a maritime boundary farther south that encompasses valuable fishing grounds (though it skirts around South Korean-held islands