During the 1980s and 1990s, Gaddafi, in alliance with the Eastern Bloc and Fidel Castro's Cuba, openly supported rebel movements like Nelson Mandela's African National Congress, Yasser Arafat's Palestine Liberation Organization, the Provisional Irish Republican Army and the Polisario Front (Western Sahara). Gaddafi's government was either known to be or suspected of participating in or aiding attacks by these and other proxy forces. Additionally, Gaddafi undertook several invasions of neighboring states in Africa, notably Chad in the 1970s and 1980s. All of his actions led to a deterioration of Libya's foreign relations with several countries, mostly Western states, and culminated in the 1986 United States bombing of Libya. Gaddafi defended his government's actions by citing the need to support anti-imperialist and anti-colonial movements around the world. Notably, Gaddafi supported anti-Zionist, pan-Arab, pan-Africanist and Arab and black civil rights movements. Gaddafi's behavior, often erratic, led some outsiders to conclude that he was not mentally sound, a claim disputed by the Libyan authorities and other observers close to Gaddafi. Despite receiving extensive aid and technical assistance from the Soviet Union and its allies, Gaddafi retained close ties to pro-American governments in Western Europe, largely by courting Western oil companies with promises of access to lucrative Libyan energy sectors. After the &lt;a href="9/11%20attacks"&gt;9/11 attacks&lt;/a&gt;, strained relations between Libya and the West were mostly normalised, and sanctions against the country relaxed, in exchange for nuclear disarmament.