As the Soviet Union began to disintegrate at the end of the 1980s, ethnic tensions grew between the Abkhaz and Georgians over Georgia's moves towards independence. Many Abkhaz opposed this, fearing that an independent Georgia would lead to the elimination of their autonomy, and argued instead for the establishment of Abkhazia as a separate Soviet republic in its own right. With the onset of perestroika, the agenda of Abkhaz nationalists became more radical and exclusive. In 1988 they began to ask for the reinstatement of Abkhazia's former status of Union republic, as the submission of Abkhazia to another Union republic was not considered to give enough guarantees of their development. They justified their request by referring to the Leninist tradition of the right of nations to self-determination, which, they asserted, was violated when Abkhazia's sovereignty was curtailed in 1931. In June 1988, a manifesto defending Abkhaz distinctiveness (known as the Abkhaz Letter) was sent to Soviet leader Mikhail Gorbachev.