The two countries established diplomatic relations on October 15, 1948. The People's Republic of Mongolia was the second country to recognize North Korea after the Soviet Union. Mongolia provided assistance to North Korea during the Korean War, although it did not directly participate, and it also contributed to the post-war reconstruction of the DPRK. On the basis of an aid agreement signed at the end of 1953, the Mongolian government sent 10,000 horses to North Korea. at Kim Il sung on a 1988 North Korean stamp. After the war, Mongolia received and brought up more than 400 war-orphaned children in 1960-1970s. From 1960 to the mid-1980s, the Sino-Soviet split – in which Mongolia adopted a consistently pro-Soviet stance, whereas the DPRK's standpoint was usually closer to the Chinese position than to the Soviet one – considerably hindered Mongolian-North Korean cooperation. On several occasions, these disagreements led to various forms of low-intensity friction in Mongolian-DPRK relations. Thanks to the post-1982 improvement of Sino-Soviet relations, in 1986 Mongolia and North Korea signed their first friendship and cooperation treaty. Kim Il-sung also paid a visit to the country in 1988. However, after the collapse of the Communist regime in Mongolia, relations became strained. The two countries nullified their earlier friendship and cooperation treaty in 1995, and in 1999, North Korea shut down their embassy in Ulan Bator on the occasion of an official visitKim Dae-jung, the first such visit by a South Korean president. Mongolia had previously expelled two North Korean diplomats for attempting to pass counterfeit United States one-hundred dollar bills.Subsequently, Mongolia began to intensify its policy of engagement with North Korea, with the aim of improving relations. In 2002, Paek Nam Sun became the first North Korean foreign minister to visit Mongolia in 14 years. The most recent high-level visit occurred in July 2007, when Kim Yong-nam, Chairman of the Presidium of the Supreme People's Assembly, made his third visit to the country; he had previously made two trips to Mongolia, in 1985 and 1988. Unofficially, North Korean visitors show significant interest in studying Mongolia's economic reforms; according to the Mongolian side, North Koreans see them as non-threatening because they are a fellow non-Western country and went through similar experiences under communism. Mongolia's efforts to introduce free-market capitalism to North Korea also have a component of self-interest. The Trans-Siberian Railway, an essential link in the potential continuous rail transit route from South Korea to Europe, passes through Mongolia; North Korean economic liberalisation which allowed South Korean shipping to pass through its borders would remove the major stumbling block to such a route, providing economic benefits for Mongolia. North Korean refugees are a delicate issue between the two governments. In 2005, South Korean charity groups received from the Mongolian government an allocation of 1.3 square kilometres of land at an unspecified location 40 kilometres outside of Ulan Bator to establish a refugee camp. However, as of November 2006, Miyeegombyn Enkhbold, Mongolia's prime minister, officially denied the existence of such camps. One scholar estimated that 500 North Korean refugees enter Mongolia each month, along with some legal migrant labourers who come under an inter-governmental agreement to work in light industry and infrastructure projects. In 2013, the Mongolian PresidentTsakhiagiin Elbegdorj visited North Korea, and the two countries expanded economic ties, particularly with regard to oil refining. In October 2018, North Korean Chairman Kim Jong-un received an official invitation to pay the visit to Mongolia by President Khaltmaagiin Battulga.
