former adversaries (except China and a number of Cambodian nationalist groups), with more acknowledgement of Vietnam's goodwill towards Cambodians, though not without controversies and opposition. Vietnam's relations with fellow communist countries China and North Korea were also severely hurt due to Beijing and Pyongyang's support for the Khmer Rouge. As both nations have never acknowledged their support for Pol Pot, relations between Vietnam and the two nations have always been difficult in spite of the end of the war. During the time of the Vietnamese invasion, North Korea had supported China invading Vietnam in 1979, as well as openly endorsed China's territorial claims in the South China Sea against Vietnam. Since the end of the war in Cambodia, Vietnam has refused to support North Korea against South Korea, and has remained deeply resentful of North Korean support for the Khmer Rouge. It was not until 2007 that a Vietnamese President, Nông Đức Mạnh, finally paid a visit to North Korea, the first high-ranking visit since 1957, which was followed later by Kim Jong-un's visit to Vietnam during the 2019 Trump-Kim Summit, with the aim to repair the previously damaged relations. Nonetheless, Vietnam has openly opposed North Korea's missile tests, a testament to the old hostility. See also Allegations of United States support for the Khmer Rouge Ba Chúc massacre Khmer Krom Nong Chan Refugee Camp Nong Samet Refugee Camp Sino-Vietnamese War Nam tiến Vietnamese border raids in Thailand Vietnamese invasions of Cambodia Vietnam-Cambodia relations Notes References Citations Sources "Annual Report 2012 Cambodia Programme". (2013). United Nations Development Programme. "Cambodia UN-REDD National Programme". (n.d.). United Nations Development Programme. Bannon, Ian; Collier, Paul (2003). Natural resources and violent conflict: Options and actions. World Bank Publications. Billon, Philippe Le (2002). "Logging in muddy waters: The politics of forest exploitation in Cambodia". Critical Asian Studies, 34(4), 563–586. Clodfelter, M. (2017). Warfare and Armed Conflicts: A Statistical Encyclopedia of Casualty and Other Figures, 1492–2015 (4th ed.). Jefferson, NC: McFarland & Company. Corbera, Esteve; Schroeder, Heike (2011). "Governing and implementing REDD+". Environmental science & policy, 14(2), 89–99. Dijkzeul, Dennis (1998). "The united nations development programme: The development of peace?". International Peacekeeping, 5(4), 92-119. Kiernan, Ben (2002). The Pol Pot regime: race, power, and genocide in Cambodia under the Khmer Rouge, 1975–79. Yale University Press. Kiyono, Yoshiyuki et al. (2010). "Carbon stock estimation by forest measurement contributing to sustainable forest management in Cambodia". Japan Agricultural Research Quarterly: