linguistic:paraphrasing
Foreign relations

Bulgaria became a member of the United Nations in 1955. Since 1966, it has been a non-permanent member of the Security Council three times, most recently from 2002 to 2003. It was also among the founding nations of the Organization for Security and Co-operation in Europe (OSCE) in 1975. Euro-Atlantic integration has been a priority since the fall of communism, although the communist leadership also had aspirations of leaving the Warsaw Pact and joining the European Communities by 1987. Bulgaria signed the European Union Treaty of Accession on 25 April 2005, and became a full member of the European Union on 1 January 2007. In addition, it has a tripartite economic and diplomatic collaboration with Romania and Greece, good ties with China and Vietnam and a historical relationship with Russia.

Bulgaria deployed significant numbers of both civilian and military advisors in Soviet-allied countries like Nicaragua and Libya during the Cold War. The first deployment of foreign troops on Bulgarian soil since World War II occurred in 2001, when the country hosted six KC-135 Stratotanker aircraft and 200 support personnel for the war effort in Afghanistan. International military relations were further expanded with accession to NATO in March 2004 and the US-Bulgarian Defence Cooperation Agreement signed in April 2006. Bezmer and Graf Ignatievo air bases, the Novo Selo training range, and a logistics centre in Aytos subsequently became joint military training facilities cooperatively used by the United States and Bulgarian militaries. Despite its active international defence collaborations, Bulgaria ranks as among the most peaceful countries globally, tying 6th alongside Iceland regarding domestic and international conflicts, and 26th on average in the Global Peace Index.

Following the 2022 Russian invasion of Ukraine, Bulgaria decided to assist Ukraine; in 2023, after Gazprom illegally stopped exporting gas to Bulgaria, the country in turn stopped importing Russian oil and gas.